NicC is correct. JCL cannot analyze or manipulate data in any way. You use JCL to establish the environment for a program to execute. Period. Full stop. End of story.
The condition you appear to establish for your first IF condition is not possible to ever be equal. Similarly, the second IF statement can ever be equal.
Adding the contents of single bytes is certainly possible, but why? Assuming these are the usual 8 bit bytes, what if the sum is greater than 255? Similarly, why do the "sum" at the end. The "sum" will rapidly exceed 255.
This has to be one of the most hare brained requirement (or class assignment) I've seen posted here, and there have been some doozies.