Use program RPDASC00 to expand your Payroll Schema, sub-schemas and Rules.
Once you have the report on screen, search for ADDWT&000 to see where that operation exists. Then search for ADDWT&001, ZERO=&000 and ZERO=&001 (and possibly other variations as AMT=&, NUM-&, RTE+&, etc.
In your Payroll Schema, you could add Function PRINT with Par2 = VAR before/after a PCR to see the values of the temporary variants before and/or after a PCR.
This can be useful during debugging a new PCR, and some can be left in the schema at key points.
With a Payroll Log on screen (Simulation or Live), you can drill down into it and a double clic on function PRINT (or on parameter VAR) will enable you to see the temporary variables that exist at that point of the processing.
Note that a double click on an other Function (such as PIT) will enable you to see the Input being used, the Processing that happens, and the Output.