Maybe I got lost somewhere.  So here is the things that have to be in place for it all to work.  A shared variable(s) in the sub-report and the main report (with the same name(s)).  An unsuppressed section in the main report where the sub-report resides.  The shared variable(s) value will be available in a section after the section where the sub-report resides.

I hope this all makes sense.