if your previous grade functions codes, are correct. then to correct your edit two letters codes require you to recall based on this LinkedIn comment post
but I would want you to check your process data codes (the first grade function) to0, the same link has response further on how to recall those codes too.
go through that post, in case if you still encounter issue, you can share screenshot of your grade codes with any of us by DM.
Regards
DP