Re: simulation of payroll

Payroll Simulation can be executed even when Payroll is "Released", or when you (or someone else) is maintaining Master Data for that employee.

Payroll Calculation can't be executed for an employee when Payroll is "Released", or when you (or someone else) is maintaining Master Data for that employee.

Feature PM004 even allows you to add a "Payroll Simulation" button in IT0008 so that a simulation could be done during maintenance of IT0008.