150-155fps is not bad at all for 10gpp and 27" draw.
When you start getting into squeezing out every FPS you gotta start thinking about things like limb width, tip width, mass etc. So just out of curiosity, what kinda limb width, tip, width and taper have you got on that?
Again, I think 155fps with 500gr is very nice from a wood bow, certainly the deer will agree.