Lost Top End after Prop Recupped

[Amarillo Palmira]

I have a 200 Mercury Optimax on a 2007 Stratos 294, with a Mercury Tempest Plus Prop, 27P. I had the prop recupped at a local shop, put it back on, and my top end dropped from 74 GPS to struggling to reach 68 GPS. Hole shot is excellent, though. I took the prop back and the dude was baffled so he reset the prop back to how it brought it in. Still didn't work. I took the prop to another shop and he recupped it and burnished it a little bit for a better bite. Well, I'm still maxing out at about 68. Trying to figure out what is wrong. My prop knowledge is zero, and the best I can come up with is A. He gave me back the wrong prop and B. Somehow the engine did not adjust to the additional load from the recupped prop. Anybody have any ideas, this is maddening!! THANKS!