On the recent changes page, if you have $wgRCShowChangedSize set to false, and you have enhanced recent changes enabled in your prefs, you will still see the byte-size change for items that are "collapsed" or "grouped".
For example, this is what i see for the "collapsed" record on the recent changes:
21:01 Television Appearances (2 changes) . . (+70) . . (Page history)
And, when i expand it, to show the details, this is what i see:
21:01 (cur; last) . . userid (Talk | contribs | block) (Summary)
20:39 (cur; last) . . userid (Talk | contribs | block) (Summary)
Since i have the flag set to false, I shouldn't see the byte-changes on any records in recent changes, i think.