Booleans, lol never use them, after about 4 or 5 boolean adds yes, you will start to lose vertices with in the concaves, use 'em lose 'em, a better way to do it would be to use Splines, to create your box, and make another Spline of your choice, attach them together, then extrude, the smaller one inside the box will be the hole you want.
Cheers ;D
btw
but weld them so they are 1 vertice thick
more than 1 vertex is called a vertice, 1 vertex is called a....vertex...hmm.
also, splines don't increase polycount, no unless your too lazy enough to choose Corners under the Line creation, in MAX. If you don't create curves you don't have a problem.
CHeers again ;D