For a mid year go live for a US client, tables T558B, T558C and T5U8C have been uploaded and schema ULK9 have been run. The data has been uploaded till 12th pd. when we run Payroll for 13th period in SAP , system shows negative amount for Taxes /403( social security) and /405( medicare). If hire a test employee and run his PR with out and PR results, then system calculates all the Taxes properly and doesnot show -ve amount. When run further for 14th period, it shows correct cumulative results . your prompt help is highly appreciated as we have been trying several scenarios for the last couple of days.