I agree that 7 is the way to go, even 6 would be better with the pass oriented offenses. However, it is still a numbers thing in most of the smaller chapters. Heck, there was a thread on here earlier this year about chapters having to give away games because they do not have enough people to cover what they have, must less with two additional officials per crew.
But it is a double edged sword, with more "games" some of the younger officials can join a crew, get games and possibly stay instead of 1 or 2 years and gone because they only get sub-varsity games.
Our chapter would fit in the "give away games...do not have enough people" category. I don't know what the total number of games was that we had to give away, but the number INCLUDED some playoff games in the early rounds.
We send out several 4-man crews for 11-man games and have sent some 3-man crews for varsity six-man. If we did not assign short crews, we'd have to give away more games.
And, we DO send 1st year guys to varsity games. No choice, or again, we'd give away some more games.
Going to 7 is 100% infeasible for us. At least until a couple of weeks deep into the playoffs.