Relation between oracle OTL ,project costing and payroll

is it possible to make the payroll amount not to get affected by the time card Time and Labor with Projects

I want to enable the employee to enter their time cards so their costs are to be allocated to the project, meanwhile not to get their payroll or salaries affected by the time card Hours - because in some cases the employee can have a non-project task so he can't create a time card against the project -

as per my knowledge the enablement of OTL will lead to calculate the employee's salary based on his attendance as it will replace the Absence management , is this valid ?