ok i made a straight stave bow shot pretty good last year,, my disclaimer is I shot by myself pulling the arrow to a piece of tape, and the hand scale I used is ok, but who knows,,
and the arrows not quite 10gpp,, but here it is,,
the bow was about 51# @ 27
I pulled it to 28 and figure about 53 at 28
it was shooting512 grain arrow 181 fps,, ok the bow was fresh,,most shots were in the high 170's,,
I did tiller the bow out to 29 1/2 but did not test it at that draw,,
the bow was holding some natural reflex after being shot in,, so I am guessing cause I cant do the math,,with 540 grain arrow maybe mid 170's,,
so I think your straight stave bow is shooting close to what you think, but wouldnt hurt to check with another chrono,, so you can sleep at night,,