For your Test Employee, do a Payroll Simulation with the "Display log" box checked.
Once the log is on screen, drill down into it until you find Function P0015, and double clic on it to confirm the Input (from IT0015), the processing (in the pcr associated to the Function) and the Output (in table IT).
Try to insert your pcr immediately after Function P0015, and call it through function PIT.