If that bow is from A&H Archery, it is cut 3/16" past center. And if your side plate is the stock plate that comes from A&H that is only about 1/16" thick, that bow is screaming for a stiffer arrow. A&H cuts all their bows 3/16" past center and that my friend puts you in a whole different world then other archers.
I'm shooting a 46# @ 28" ACS with GT/5575 and 200 grain tips, standard inserts. Technically I should be shooting arrows spined at .500 ie. 3555, but to shoot heavier weight I had to move up one spine to .400, because of the bow being cut past center. I can even shoot .340 GT pro hunters 7595 with a 250 and 300 grain tip.
I ran the numbers on the Stu dynamic spine calculator, and according to the calculations, your arrows are not to far off, but your foc% is low. If you moved up to the 3555 with say a 200 grain tip your foc% would be at around 20%. It seems that everyone these days is playing with higher foc trying to get above 20%.