We need answer JSON only. Need calculate under rules. Need inspect inputs.

Payroll record: gross_pay 4326.01, month 2026-03, allowed_deduction 386.64. Authoritative case schedule first-half applies for 2026-01 through 2026-06. Need use supplied values replacing defaults. first-half: rate 0.07, cap 4500.00, deduction cap 400.00, free 1200.00, upper 3600.00, middle_rate 0.08, upper_rate 0.18.

Need calculate employee_contribution = rate * min(gross, cap) = 0.07 * 4326.01 = 302.8207 -> round half-up two decimals = 302.82? Let's compute: 4326.01*7/100 = 302.8207. Third decimal 0? Actually 302.8207, hundredths = 2? Number 302.8207: digits 302 . 8 2 0 7. To two decimals: 302.82 if third decimal is 0, yes. Employee contribution 302.82.

Allowed deduction = 386.64. Must not exceed selected deduction cap 400.00 or gross_pay minus rounded employee contribution = 4326.01 - 302.82 = 4023.19. So 386.64 <= both. OK.

Taxable pay = gross - employee contribution - allowed deduction = 4326.01 - 302.82 - 386.64 = let's compute. 4326.01 - 302.82 = 4023.19. -386.64 = 3636.55. Yes.

Income tax progressive:
Tax-free amount 1200.00. Upper bracket begins 3600.00. Taxable pay 3636.55.
Portion up to free untaxed: 1200.
Portion above free up to upper: taxable pay? Need "portion above that amount up to upper-bracket boundary uses middle rate." That is min(taxable, upper) - free = 3600 - 1200 = 2400.00 at 8% = 192.00.
Portion above upper: taxable - upper = 3636.55 - 3600 = 36.55 at 18% = 6.579 -> round? Rule R2: Do not round intermediate bracket products separately before summing income tax. Round total income tax under R2. So total = 192 + 6.579 = 198.579. Round half-up to two decimals = 198.58? Need half-up on 198.579 -> third decimal 9, so 198.58? Wait 198.579, to two decimals: hundredths = 7? Let's parse: 198.579. Digits after decimal: 5 tenths, 7 hundredths, 9 thousandths. Rounding to two decimals: look at thousandths 9, round up hundredths 7 to 8 -> 198.58. Yes.

Net pay = gross - employee_contribution - allowed_deduction - income_tax = 4326.01 - 302.82 - 386.64 - 198.58. Compute taxable 3636.55 - 198.58 = 3437.97. Alternatively 4326.01 -302.82=4023.19; -386.64=3636.55; -198.58=3437.97.

Need return decision calculate, currency LCR, fields strings two decimals: gross_pay "4326.01", employee_contribution "302.82", allowed_deduction "386.64", taxable_pay "3636.55", income_tax "198.58", net_pay "3437.97". Clauses? Calculated answers cite R1 through R6, and also R9 only when amendment needed. No amendment. So clauses ["R1","R2","R3","R4","R5","R6"]? R6 says provide clause references. The answer fields only clauses. Need maybe include R1-R6. R1 selects reference, R2 arithmetic, R3 contribution, R4 deduction/taxable, R5 tax, R6 net/answer. Good.

Need ensure exactly required answer fields and only clauses that directly govern. Could include explanation optional. The prompt: "Return one JSON object without Markdown fences... An optional explanation string is permitted. Do not include input-only fields..." We can omit explanation. Need no markdown.

Check if any ambiguity: The authoritative schedule: first-half deduction cap 400.00. allowed_deduction 386.64. OK. Is allowed deduction "must not exceed selected deduction cap or gross pay minus rounded employee contribution." Both. Good.

Potential issue: "When showing old and current rows together, only the row covering the payroll month applies." Here only first-half. OK.

Potential issue: reference_tables "first-half" and "second-half" numeric values replace defaults. We use first-half. Good.

Need output valid JSON. All money strings two decimals. Currency LCR. decision calculate. clauses maybe array of strings.

Let's final.

We need answer JSON only. Need process payroll.

We have case reference schedule replaces defaults. Payroll month 2026-03 -> first-half. Values:
rate 0.07, cap 4500.00, deduction cap 400.00, free 1200.00, upper begins 3600.00, middle 0.08, upper 0.18.

Input gross 4326.01, allowed_deduction 386.64.

Need calculate.

Check R7: gross present, payroll month present. allowed_deduction omitted? present. Need validate R2: money non-negative decimal at most two fractional digits. gross 4326.01 ok. allowed 386.64 ok.

R3 employee contribution = rate * min(gross, wage cap). min(4326.01, 4500.00)=4326.01. 0.07*4326.01 = 302.8207. Round half-up to two decimals = 302.82? 302.8207 -> third decimal 0? Actually 302.8207: two decimals 302.82, third decimal is 0? Let's compute: 4326.01 * 7/100 = 302.8207. digits: 302 . 8207. hundredths: 2? 302.82 with next digit 0? Wait 302.8207: decimal digits 8 (tenths), 2 (hundredths), 0 (thousandths), 7. So round to 302.82. Yes.

R4 allowed_deduction must not exceed selected deduction cap 400.00 and gross minus rounded employee contribution. gross - contribution = 4326.01 - 302.82 = 4023.19. 386.64 <= 400.00 and <= 4023.19. ok.

Taxable pay = gross - employee contribution - allowed deduction = 4326.01 - 302.82 - 386.64.
4326.01 - 302.82 = 4023.19. -386.64 = 3636.55. Let's do decimal: 4326.01 - 689.46 = 3636.55. Yes.

R5 income tax progressive:
Taxable pay 3636.55.
Tax-free amount 1200.00 untaxed.
Portion above free up to upper boundary 3600.00: from 1200 to 3600 = 2400.00 taxed at middle rate 0.08 = 192.00.
Portion above upper boundary: taxable 3636.55 - 3600.00 = 36.55 taxed at upper rate 0.18 = 6.579. 36.55*0.18 = 6.579. Round? Rule: Do not round intermediate bracket products separately before summing income tax. But total income tax round under R2. So total = 192.00 + 6.579 = 198.579. Round half-up to two decimals = 198.58? Need examine: 198.579 -> two decimals. 198.579 digits: hundredths = 7? Let's write 198.579: tenths 5, hundredths 7, thousandths 9. Round up hundredths from 7 to 8 -> 198.58. Yes.

R6 net pay = gross - employee contribution - allowed deduction - rounded income tax.
4326.01 - 302.82 - 386.64 - 198.58.
Already taxable 3636.55 after contributions/deduction. subtract tax 198.58 = 3437.97. Let's compute: 3636.55 - 198.58 = 3437.97.

Need output decision calculate, currency LCR, fields as strings two decimals:
gross_pay "4326.01"
employee_contribution "302.82"
allowed_deduction "386.64"
taxable_pay "3636.55"
income_tax "198.58"
net_pay "3437.97"
clauses citations supporting. Calculated answers cite R1 through R6, and also R9 only when amendment needed. No amendment. So clauses ["R1","R2","R3","R4","R5","R6"]? "Provide clause references supporting calculation." Use exactly required fields and only clauses that directly govern answer. R1 scope/ref, R2 money arithmetic, R3 contribution, R4 deduction/taxable, R5 tax, R6 net/format. Include all R1-R6. Maybe not R7 because no clarification. Need no explanation? Optional. Could include no explanation.

Need ensure JSON object no markdown. Use allowed fields. Good.

Double-check arithmetic:
Employee contribution: 4326.01*0.07 = 302.8207 -> round 302.82.
Allowed deduction cap 400.00, available gross-contribution 4023.19. OK.
Taxable = 4326.01 - 302.82 - 386.64 = 
4326.01 - 302.82 = 4023.19. -386.64 = 3636.55.
Tax:
taxable - free = 3636.55 - 1200 = 2436.55.
Middle bracket width = upper - free = 3600 - 1200 = 2400. Tax 192.00.
Upper = 36.55*0.18 = 6.579.
Sum 198.579 -> 198.58 (round half-up? 198.579 -> 198.58 yes because third decimal 9).
Net = 4326.01 - 302.82 - 386.64 - 198.58 = 3437.97.

Need consider R2 "Do not round intermediate bracket products separately before summing income tax." We didn't. Good.

What about "allowed_deduction defaults to 0.00 when omitted. It must not exceed selected deduction cap or gross pay minus rounded employee contribution." 386.64 <= 400.00. yes.

Could there be invalid because allowed_deduction 386.64 is less than cap but gross pay minus contribution? yes.

Need output.

We need answer JSON only. Need calculate under rules. Need be careful with reference schedule authoritative replaces defaults for case. Month 2026-03 first-half row schedule: rate 0.07, cap 4500, deduction cap 400, free 1200, upper 3600, middle 0.08, upper 0.18.

Input gross 4326.01, payroll_month 2026-03, allowed_deduction 386.64. No contract_gross_pay? Source only payroll. Need calculate.

Employee contribution = rate * min(gross, cap). min(4326.01, 4500)=4326.01. contrib = 0.07 * 4326.01 = 302.8207. Round half-up to 2 decimals = 302.82? 302.8207 -> 302.82 because third decimal 0? Let's compute: 4326.01*7/100 = 30282.07/100? 4326.01*7 = 30282.07, /100 = 302.8207. To two decimals: 302.82 since third decimal 0? Actually 302.8207: hundredths = 2? Let's parse: 302.8207. Digits after decimal 8 2 0 7. Two decimals = 302.82, third digit 0, yes.

Allowed deduction defaults omitted? present 386.64. Must not exceed selected deduction cap 400.00 or gross pay minus rounded employee contribution. gross - employee = 4326.01 - 302.82 = 4023.19. 386.64 <= both. So allowed 386.64.

Taxable pay = gross - employee contribution - allowed deduction = 4326.01 - 302.82 - 386.64 = 3636.55? Compute: 4326.01 - 302.82 = 4023.19. minus 386.64 = 3636.55. Yes.

Income tax progressive. Tax-free 1200. Upper bracket begins 3600. Taxable 3636.55. Tax = portion between free and upper * middle + portion above upper * upper.
Middle taxable = 3600 - 1200 = 2400.00 * 0.08 = 192.00.
Upper taxable = 3636.55 - 3600 = 36.55 * 0.18 = 6.579 -> round? Rule R2: Do not round intermediate bracket products separately before summing income tax. Need sum exact products then round total. 36.55 * 0.18 = 6.579. Total = 192 + 6.579 = 198.579. Round half-up to 2 decimals = 198.58? Third decimal 9, so 198.58? Wait 198.579: hundredths: 7? Let's parse 198.579. Decimal digits: 5 7 9. To two decimals, look at third digit 9 -> round up second digit 7 to 8: 198.58. Yes.

Net pay = gross - employee contribution - allowed deduction - income tax = 4326.01 - 302.82 - 386.64 - 198.58.
Already gross - employee - allowed = taxable 3636.55. Minus tax 198.58 = 3437.97. Compute: 3636.55 - 198.58 = 3437.97. Or 4326.01 - 302.82 = 4023.19; -386.64 = 3636.55; -198.58 = 3437.97.

Need clause references. Calculated answers cite R1 through R6. Also R9 only if amendment needed. No amendment. So clauses ["R1","R2","R3","R4","R5","R6"]. Maybe include R1 for row selection, R2 arithmetic, etc. Need exactly required answer fields. Fields: decision, currency, gross_pay, employee_contribution, allowed_deduction, taxable_pay, income_tax, net_pay, clauses. Money strings two decimals. decision "calculate", currency "LCR".

Need ensure employee contribution rounding: 302.82. Allowed deduction 386.64. Taxable 3636.55. Income tax 198.58. Net 3437.97.

Let's double-check with defaults? Authoritative schedule replaces defaults. Yes schedule has first-half for Jan-Jun. Month 2026-03.

Need maybe allowed_deduction cap in schedule is deduction=400.00. Input 386.64 valid. Available pay check gross - rounded contribution = 4023.19. Good.

Need output JSON only no markdown. Use exactly fields and clauses. Optional explanation permitted? Not needed. Must not include input-only fields. Good.

Potential issue: R2 says round monetary calculation results to two decimals using round-half-up. For contribution 302.8207 -> 302.82. For income tax: do not round intermediate bracket products separately before summing. We did exact. But should we round total 198.579 to 198.58. Yes.

Let's consider if taxable pay should be rounded? It's subtraction of rounded employee contribution and allowed deduction from gross. Gross and deductions are two decimals; result 3636.55 two decimals. No issue.

Potential subtlety: Employee contribution uses selected contribution rate multiplied by smaller of monthly gross pay and selected wage cap. If gross=4326.01, cap=4500.00. Contribution = 302.8207. R3 says Round the contribution under R2. So 302.82. Then R4 subtract rounded contribution. Good.

Could there be issue allowed deduction must not exceed gross pay minus rounded employee contribution. It doesn't. Good.

Let's craft JSON. Ensure no extra prose. Use strings. clauses array order maybe R1-R6. 

Final.