Spreadsheet Failure ModeManual Workflow
Root Operational Bottleneck
W-4 and tax-status changes are typed from HR forms into a payroll override sheet, so the next pay run still withholds at the prior filing status.
Control Hazard & Audit Exposure
Mid-year status changes miss the pay period they were effective, producing under- or over-withholding that is only corrected on a later amendment.
Deterministic Software ReplacementClient-Owned Architecture
HRIS Tax-Status Change Webhook with Same-Pay-Period Withholding Recalculation
HRIS tax-status webhook that writes the new filing status and effective date into payroll and recalculates withholding for the next locked run.
Continuous Assertion Rule
Status assertion: a pay run cannot lock if any employee has an HRIS tax-status change effective on or before the check date that is not applied to that run.