See 20xx FCD "8.5.1.6.3 Dynamic-capacity tables"
This is currently partly in the compiler - see parser.y PENDING("OCCURS with DYNAMIC capacity" and completely missing in runtime.
Simon
Discussion: dynamic capacity tables
Wish List: #109
Patches: #30
I've started work on this. I've posed some questions to https://sourceforge.net/p/open-cobol/discussion/contrib/thread/c70737d6/.