CRT is sum of RT i.e Wage type YYYY amount of Jan + Feb + Mar ......Dec this can be configured through table V_T54C3 and Processing class 30 which updates the CRT.
Now what we can do is let assume that we wanted to read CRT value of wage type
in the month of April
YYYY = 1000 Jan
YYYY = 1000 Feb
YYYY = 1000 Mar CRT will have YYYY = 3000 till march
when am executing April payroll i wanted to bring CRT of YYYY to current month since
we will write a rule where XXXX is holding 1000 in Input table
XXXX
AMT=CYYYY now amount will become 3000 which is YYYY of CRT
AMT+CYYYY now amount will become 1000+3000 which is IT XXXX+YYYY of CRT
XXXX is available in IT since i will use PIT PCR1 GEN NOAB
In case XXXX is not available in IT it is available in RT in such cases
PRT PCR1 GEN NOAB.
so simple thing is in log you have to check the wage type which you are using in PCR should be available in IT then PIT.
Regards
Venkatesh