Salary slip from timesheets does not record multiple activity costs

I have employee that has two different activity costs during the work week. The timesheets reflect the shifting rates of the activity costs. When I create a salary slip from those time sheets, the salary slip defaults to the rate in the salary structure and ignores the actual shifting activity costs in the timesheets. Is there a way to have the Salary Slip track the rate from multiple activity costs in the timesheets? This is a basic timesheet function. Salary Slips should be able to track activity costs.

If there is not a way, then how to account for multiple activity costs for 1 employee?

Thank you