I doubt this API will then help to clear it up:
I suspect that IBM changed the behavior at some PTF level.
Good luck determining that.
You'll have to make a decision as to whether or not you face the loader
full risk by not having that PTF definitively listed as "Permanently
Applied" vs just "superseded". Unless the "superseeding ptf" is also
permanently applied. If so, you should then be good to go.