I use the IBM guidelines and haven't had a problem. A called program that assumes it received a 72-byte save area does not corrupt the large save area, it just isn't "correct". But it causes no problem.
I don't see your distinction between the save areas that provide space for the caller's high-halves and you picking somewhere else to put them. As far as I know, no diagnostic tool keeps up with the various z/OS linkage conventions. Certainly not SYSUDUMP. It might require AI to track back through various savearea formats, linkage stack, and LINKs, not to mention all the things that don't follow convention. It is messy, and the documentation is long (and boring) but IBM covered all the bases pretty well. sas
