I would go ahead and crank it up. Bows are supposed to shoot their best the closer you get to maxed out. Any re-tuning will probably be minimal.

That said, I still wouldn't worry about the speed too much. I had pass-thru kills on nearly every deer I shot in my early bowhunting days . . . and I was shooting a Darton SL50 wayback then that consistently chronographed @173 fps!