I posted this on the MAC site but was not clearly worded.
Looking back in D7 region 28 over the 5 year period of 2015-2019 the 16th place finisher only needed 3 wins most of the time if the opponets they defeated had a combined minimum of 4 wins ( ie. 0-10, 3-7, and 1-9 = 4 combined wins).
With that information, I then tried to figure the probability of how many teams out of 8 would get at least 3 wins. The worst case scenerio is for a league to have perfect decending ability with teams going 7-0, 6-1, 5-2.........1-6,0-7. That gives 5 teams three wins just in conference play. Best case scenerio is 7 teams go 4-3 in conference play and one team goes 0-7. That scenerio would never happen in high school football as teams have too much disproportionate talent and ability. More likely is top four teams all defeat bottom four. That means in the bottom 4 pool you would have these teams producing potential records against each other in the pool of (3-0, 2-1 1-2,0-3) or (2-1,2-1,2-1,0-3) or ( 2-1,2-1,1-2,1-2).
In actual likelihood, one of the bottom four will defeat a team from the top four, and it's likely to be a team that defeated two other of the bottom four, so that team would also have 3 wins just from conference play. If you allow for each of the bottom four to get one win from out of conference then you have a very real possibility that at least 5 of the eight make the top 16 in their region, and by my calculations, a greater than 50% probability that 6 get in so long as they have 1 OOC win.