More than likely you are getting false readings off of the stiffest shafts.
That bow being cut 3/16" past center will need a stiffer shaft than other bows not cut so deeply, but not the 200 spine.
Do you shoot three under? if so, do you have string nocks above and below the arrow?
Try building the side plate out some. The small diameter shafts can give you fits on that deep of a sight window. It is conceivable that instead of being center shot, it is actually past center shot and a nightmare to tune.
If you build out the sight window and things start getting better, than it should prove that the shafts are truly too weak, or you were shooting past center shot.
I know that most get the tunnel vision that says for a right handed shooter ...nock left is weak and nock right is stiff but If the arrow is too stiff and hits the side plate or shelf, it will likely show too weak. If the nock point is too low, it will hit shelf and can show too weak. If arrow nocks are too tight, it can show weak. If arrow is shot from a past center cut bow, it can show too weak. Without a nock point below the arrow for a three under shooter, it can show just about anything.
Are ya getting my drift here?
I shoot a full length 300 spine arrow out of a 1/8" cut past center bow with 311 g up front. I draw right at 32" and when I am "right", I can shoot that shaft at 25 yards and it flys perfectly, but it never ever flys stiff...If I short draw, it flys weak (I'm apparently hitting the bow with a short draw).
Going with lighter points will only cause the arrow to straighten out and appear to fly true, but will really just make it look better but it will never come back around to line of sight.
Lots of things to take in...give me a call if I can be of assistance.
BigJim