Payroll cost distribution to PPM - Benefits distributed to Projects

Hi wizards,

The goal is to use the functionality of the Payroll cost distribution to PPM to distribute the employer taxes to PPM.
The employee will enter his timecard in OTL on the POET attributes. the elements he will be entering in OTL on the Project and Task attributes are regular hours, overtime, double time.
Question:

How to instruct Oracle Payroll to distribute the Payroll employer taxes and benefits to PPM based on the hours allocated in OTL ?

should we create a Labor schedule by combination of person assignment and pay element? or simply use the Labor schedule by assignment only?