2. Classification of the chips

Experience has shown that it hardly makes a difference who has a few more or less chips if two players have an even chip stack.

MP1 would theoretically have to regard this as an all-in situation if he receives a push from the button (disregarding every other player), as he would only have 135 chips left if he loses, which is a bit more than one big blind and won't really help him anymore.

The BB with only 55 chips more than UTG+1 has no advantage either. With 2,135 chips, he is for UTG+1 the same threat he would be with only 1,800 chips: In both cases a lost confrontation with UTG+1 would mean almost certain elimination, as his situation with 280 chips is almost as bad as with 0 chips.

Two (or more) players are in a group, as long as the bigger stack doesn't have >35% more chips than the smaller one.

The reason for this will be explained later. As mentioned before, it hardly matters who of the two has the bigger and who the smaller stack.