Suny, I think it would behoove you to learn something about CICS before posting in a CICS forum.
You never need to move PICIN to PICOUT -- or PICOUT to PICIN -- since they are the same field and occupy the same bytes of memory. If you are writing CICS programs that do things like this, you completely wasted whatever money you spent to learn CICS.
Stating a program will abend due to a comma in a PIC X variable indicates you know nothing about COBOL, either. A PIC X variable can contain numeric, alphabetic, special character, and even non-printing characters -- any of the possible 256 EBCDIC bytes can be placed in a PIC X variable. A CICS program will not abend just because a comma is in a PIC X(08) variable.
Also, research BIF DEEDIT in a CICS Application Programming Reference manual or NUMVAL in a COBOL Language Reference manual. Both of these can be used to process the PICIN X(08) variable -- or reference modification could be used, not to mention an array to handle each byte seperately.
And I explicitly stated processing of the PICIN variable would be needed. The original question was when would different PICIN and PICOUT be used and I gave an example. The original question did not mention MDT so your adding it the equation changes the original question to something different.