Did you have to regenerate any of the programs that OSS Note 44410 originally specified to do when implementing structure ZMMH1?
I'm considering doing the same thing you are (deactivating ZMMH1), but when I look in program RMDATIND, I see generated code in include RMDATINZ for the structure ZMMH1. Just curious if you regenerated programs after you disabled the structure, and if the code for ZMMH1 went away.