ORIGINAL: davepjr71
Something seems off on the increased IBO speed. You shouldn't need to adjust the IBO speed of your bow. It is what it is. Just change the input numbers for the heavier arrow.
This is from the help file of OT2:
The bow performance slider can be used to change bow efficiency as it relates to the IBO/AMO velocity. Changing the slider will alter the the program calculation for arrow velocity. Altering the performance factor will also affect the way the program makes shaft selections on the Spine Match Tab. Using a higher performance factor will result in the program selecting stiffer shafts. A lower performance factor will result in weaker shafts being selected. If all you need to do is synch the program calculation to your known velocity, a better way is to just change the IBO or AMO velocity values until your known and the calculated velocities match.
The bold is from OT2, the italics and underline are my highlight. If I read this correctly then When I take my known arrow weight (and known weights of all the parts - 22gr insert, blazers weighed @ 6gr each, nock weighed @ 12gr, 200gr point and the shaft) and shoot it and then get my known chrono speed then I should be able to adjust the IBO speed to match my known chrono speed.
OT2 is only as accurate as the numbers put it. I put in as many measured, known numbers as possible. Anyway all I did was synch the program calculation to my known velocity as outlined in the help file. And it seems that the numbers say my bow is more efficient at a higher arrow weight.