[@Lutalica]
That'd be true, actually. A FRAME with 2 slots could carry an autocannon and one more weapon; anything of your choice.
Considering that an autocannon to a FRAME is akin to a standard-issue rifle for infantry, I hope that sounds reasonable. In most cases, FRAMEs will trade weight for power, and vice-versa, but later on, some really high-grade machines might have lots of both.

Also, don't forget antipersonnel machine guns are mandatory as well, but don't count towards the total.