Time Management Aspects in Payroll 
The Time Management (PT) and Payroll (PY) components are closely linked in the R/3 System.
The processing of time data for determining the gross wage takes place in the gross part of payroll. Subschema xT00 (x=country indicator) is used to process Time Management aspects within Payroll.
These include:

It is possible that differences between the times from the personal work schedule and the planned times may affect the monetary valuation of work performed. This may happen if an employee has substituted for another employee, for example.
Processing Incentive Wages