svt 3 non-pro

So I have this Ampeg SVT III (non-PRO) rackmount head, churns out 300W @ 4ohms. I also own a Mesa/Boogie 4x10 Powerhouse bass cab, rated 8ohms. After asking around to figure it out, I now know that my cab is pushing about 150W, which is half the power I could be getting if I were running every...