I assume that if you have captured a point that's between 2 enemy points, that yours will spawn minions on both sides.

If that's the case then no matter how many flags either team has captured, the number of minion waves will always be equal for both sides.

As for the max number of waves, I would assume it is 4. If you have both bottom caps and the top, each bottom will have one wave, and the top will have 2 (since enemy caps are on both sides).