This is expected behavior.
According to the Startup Command and Parameter Reference, Startup Parameter Descriptions : Registry Base Key (-basekey):
Note: You can use the -basekey startup parameter only at the command line. It is ignored when used in a parameter (.pf) file.
The same restriction is documented for the -ininame startup parameter.
The AVM follows the set of rules detailed at Progress Documentation: Searching progress.ini and the Registry at startup (
https://docs.progress.com/bundle/openedge-abl-manage-applications-117/page/Searching-progress.ini-and-the-Registry-at-startup.html) .