Doesn't take me 15-20 minutes, most of the groups I end up with of L28-29's, takes about 10 - 12 minutes. You can't even run through all the groups in the strikes. You are talking complete shit. There is no way skipping 2 or 3 groups takes 5 minutes or more off a strike. With 3 good players you can kill most groups without even stopping moving forward.