Slats, Brian; well said, lads, well said.
JC, you didn't have a fitting - you had a 4 ball demo of one club.
Did you go in thinking you were going to buy MP60's, and decide to have them fit for you? Or did you go in with the mindset that you're going to try things, and see what works best, regardless of brand?
Either way, hitting two balls to 'see if the shaft is OK' is junk. Now, hitting 2 or 3 balls
with different flexes of shafts is much better - who's to say that you wouldn't have done better with a different flex shaft - or a different make of shaft altogether?
Also, I'd like to point out that just because two
clubs have Winn G8 grips, True Temper DG R300 shafts, and
Mizuno MP32 6 iron heads does NOT mean they are the same
clubs.
As for lie adjustment, every club should be lie tested before taking them home.