KCee There is a HUGE difference between each different head. The tolerances that manufacturers will accept is what it all comes down to. There were a lot of people in the early 2000's losing their minds when they would get a TM head that was 4 or more degrees off from what it was stamped, almost ALWAYS higher in loft, which ironically as they tightened specs, they had a loft up campaign.. shocking I know.
The reason so many people will hit a club at demo days, kill it, order one and can't come close to duplicating it is the tolerance issue. Even at +-1 degree may mean the club you hit at demo days that said it was a 10, might have been an 11, with a 1* closed face angle and lets say for shits and gigs, it had a 246cpm shaft. You order that exact same combo you were htting, but without getting it precisely measured, you may get a 9 degree head that sits a 1 degree open and a shaft that cycles out a 252cpm and has a completely different flo orientation than what you hit. Oh and now we change the shaft orientation via an adapter and really screw up the shaft performance. So much fun.
Moral of the story, you find the one you like, act like its a woman, take that one home, her identical looking sister will never quite do it for you.