I can't really say, because I usually just adjust food by 1/4 cup up or down until they are back to a weight I prefer. You can still feed the 30/20, just feed less of it.
You can add some low salt green beans to help her feel full, I know people do that, but they ARE Labs they never feel full LOL :-) It may take you a few weeks or a month or so to drop that 5 lbs, make sure you up her exercise a little too.
Good luck!