Yes, if you create a formula in the subreport footer that shares the value:
whileprintingrecords;
shared numbervar x := <your sub value here>;
Then in the main report, in a section below the one containing the subreport, e.g., in GHb if the sub is in GHa, use a formula like this:
whileprintingrecords;
shared numbervar x;
x * {main.qty} //sample calculation
-LB