If your beater is like a Ball, or a Pearl Quad-beater, the angle won't matter too much since it's rounded. If it's like some of the speed pedals which have a completely flat-head (like my Trick Pro-1Vs), it definitely matters, but can be adjusted.
For most beater types, you're ok... or you can just get a rounder beater and replace your current one.
I've noticed my beater hits the head at a slight angle, past 90 degrees. I assume exactly 90 degrees is preferred, but I see no way to adjust anything to change it. Am I missing something? I have a DW5000.