My understanding is that you break a 3 way tie by looking at point differential among the three teams when they played each other. Largest point differential gets the #3 seed.
Now you're down to two teams tied for the #4 seed, and you go back to head-to-head.
Given that, here's the breakdown. If Valley City beats Grafton, and there are no other major upsets, it creates a 3 way tie with Valley City, Grafton and Central Cass
Central Cass beat Valley City by 4 and lost to Grafton by 12, for a point differential of -8
Grafton beat Central Cass by 12 and sits +12
Valley City lost to Central Cass by 4 and sits -4
If Valley City beats Grafton by 9 or more points, they will win the #3 seed on point differential. Grafton would get the #4 seed, having defeated Central Cass head to head.
If Valley City beats Grafton by 8 points, they will tie Grafton on point differential at +4, with both teams ahead of Central Cass in points. I would assume they break this two way tie by going back to head to head, and Valley City would get the #3 seed. Grafton gets the 4 seed again due to their head to head win.
If Valley City beats Grafton by 7 points or less, Grafton would get the #3 seed on point differential. Central Cass would get the #4 seed due to their head to head win over Valley City.
To me, it looks like Valley City has to beat Grafton by 8+ points to make the playoffs, and if they do, they'll be the 3 seed.
Looks like Grafton is sitting pretty good. I don't see a scenario where they would miss the playoffs. If they win, they're the #3 seed. If they lose, they'll be #3 or #4, depending on the margin.
Central Cass is rooting for Grafton to either win the game or keep it within 7. The best they can do is the #4 seed.
Clear as mud?
And if I'm wrong, can someone correct me?