{
 "task_id": "T06",
 "run": 3,
 "prompt": "A raise was approved six weeks late. Compute retro pay across three periods with a 401(k) deferral.",
 "system": "You are a payroll assistant at a US company. Answer the request.",
 "model": "claude-opus-5-5",
 "response": "# Retroactive Pay Calculation: Raise Approved 6 Weeks Late\n\nYou didn't include employee figures, so below is a **worked example with stated assumptions**. Replace them with the actual values and the method stays the same.\n\n## Assumptions (replace with actual data)\n\n| Item | Example Value |\n|---|---|\n| Pay frequency | Biweekly (6 weeks = 3 pay periods) |\n| Old annual salary | $65,000 |\n| New annual salary | $70,000 |\n| Effective date | First day of Period 1 (no mid-period proration) |\n| 401(k) deferral election | 6% of eligible compensation (pre-tax) |\n| Federal withholding | 22% flat supplemental rate |\n| State withholding | 5% (illustrative only, varies by state) |\n| Employee is below the SS wage base and the 401(k) annual limit | Yes |\n\n## Step 1: Gross Retro Pay\n\n| Period | Paid (Old Rate) | Should Have Been Paid (New Rate) | Difference |\n|---|---|---|---|\n| Period 1 | $2,500.00 | $2,692.31 | $192.31 |\n| Period 2 | $2,500.00 | $2,692.31 | $192.31 |\n| Period 3 | $2,500.00 | $2,692.31 | $192.31 |\n| **Total** | | | **$576.92** |\n\n*Computed as ($5,000 \u00f7 26) \u00d7 3 = $576.92 to avoid rounding drift. Summing the rounded rows gives $576.93.*\n\n## Step 2: 401(k) Deferral\n\n- $576.92 \u00d7 6% = **$34.62** pre-tax deferral\n- If the plan has an employer match (e.g., 50% up to 6%), the employer also owes **$17.31**.\n\n## Step 3: Taxable Wage Bases\n\n| Tax | Wage Base | Why |\n|---|---|---|\n| Federal income tax | $542.30 | Gross minus the 401(k) deferral |\n| State income tax | $542.30 | Most states exclude 401(k) deferrals. PA does **not**, so it would use $576.92. |\n| Social Security / Medicare | $576.92 | 401(k) deferrals do **not** reduce FICA wages |\n\n## Step 4: Withholding and Net Pay\n\n| Line | Calculation | Amount |\n|---|---|---|\n| Gross retro pay | | $576.92 |\n| 401(k) deferral | 6% \u00d7 $576.92 | \u2212$34.62 |\n| Federal income tax | 22% \u00d7 $542.30 | \u2212$119.31 |\n| Social Security | 6.2% \u00d7 $576.92 | \u2212$35.77 |\n| Medicare | 1.45% \u00d7 $576.92 | \u2212$8.37 |\n| State income tax | 5% \u00d7 $542.30 | \u2212$27.12 |\n| **Net retro pay** | | **$351.73** |\n\n**Employer-side costs:** SS $35.77 + Medicare $8.37 + FUTA/SUTA (only if the employee is still under those wage bases) + any 401(k) match.\n\n## Compliance Notes\n\n1. **Retro pay is taxed when paid, not when earned.** It counts toward the current year's W-2, even if the raise was effective in a prior year.\n2. **Supplemental wage method.** You may use the 22% flat rate if retro pay is identified separately from regular wages. Otherwise, use the aggregate method, which combines it with a regular paycheck and withholds per the W-4.\n3. **401(k) eligibility.** Confirm that the plan document's definition of compensation includes retro pay, and apply the employee's *current* election. Check the 402(g) limit ($23,500 for 2025, plus catch-up contributions if eligible).\n4. **Hourly or non-exempt employees.** Recalculate overtime for each affected period. The regular rate increased, so OT owed is (new rate \u2212 old rate) \u00d7 1.5 \u00d7 OT hours, in addition to the straight-time difference. This is an FLSA requirement.\n5. **Mid-period effective date.** Prorate the first period by working days or hours at each rate.\n6. **Other deductions.** Flat-dollar deductions like health premiums don't change. Percentage-based ones do, such as some garnishments, union dues, and life insurance tied to salary.\n\n## To Run the Actual Calculation, Please Provide:\n- Old and new rate (annual salary or hourly rate)\n- Pay frequency and the raise's effective date\n- Hours and overtime per period (if non-exempt)\n- 401(k) election (percentage or flat amount, pre-tax or Roth) and match formula\n- Work state (and locality, if applicable)\n- Whether you'll pay it as a separate check or add it to a regular paycheck\n- Year-to-date wages and 401(k) contributions (to check limits)",
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