Its kinda tricky. There is more to fix besides the division champ and wild card calcluations.
You also have to change the whole playoff structure and how it draws the teams for the playoff bracket one the regular season is over
The reason why you get buffalo vs buffalo is the memory locations that are now empty for the wild card games default to zero (buffalos team id) hence why you get buffalo vs buffalo for at least the first 4 games that no longer exist.