This makes me VERY nervous! I am one of the huge number of players who use the Calloway i(s) balls, and I've used them for a long time. All my clubs are rated using these balls with all the different shots available, with no spin, top spin and backspin, to do this I hit the ball on a relatively flat fairway in two opposing directions with low wind and average the distance. This means a LOT of hits lets say 13 clubs, just 4 different shots, full, punch, pitch and flop, so
13 x 2 (opposing directions) x3 (different spin) x 4 (shots) = 312 shots.
That's a lot of balls and time to waste if the distances change!