I don't know the answers to your questions, but I think some of the output is calculated based on parameters they input before you swing. So I'd guess they have a way to compensate for the ball.

What is/are the difference(s) in the 907 and G15?

My 907D2 is 9.5 degrees, with a stiff YS-6, with stock length.

The G15 I was fit for was a 10.5, with graphite Rifle 6.0, 1/2" short. (Still about 1" longer than my 907D2).

I would definitely like to know if the launch monitor calculates the effect of the ball.

When I did a club fitting we used Pro V's. He did ask me what ball I used so I figured it would be more realistic. They seem to want to use your current driver as a base so you would think they should use the same ball also.

Jeff,

 In personal opinion, I think that you should never trust a fitter that uses a range ball. Example: Last time I was being fit for a driver the fitter was using some ball that you can get for $8.00 a dozen. After hitting 30 drives with 3 different drivers he asked, "Which one feels best?" My reply was, "What do the numbers say?". His reply, "There all the same." At this point I was frustrated and confused. How could 3 different drivers, with different shafts and lofts all produce the same result. Hmm, that's just not right. So, I asked him for a break and ran to the car. I grabbed a sleeve of ProV1x and headed back in to try it again. This time I was seeing noticeable difference in numbers. (For clarity, when I say numbers, I'm referring to Backspin, Launch Angle, Smash Factor, Ball Speed and Distance) These are all very crucial in determining the best fitting and feeling driver for a player. So, does it make a difference? YES! If the fitter were to tell you that the newer club will only gain you 1-2 yards in distance, what would be the reason to buy it? None. Best advice on this subject. BRING THE BALL YOU PLAY! It's the only way you will determine the best fit. Also, take the time to research and understand the meaning of the numbers your getting and looking for, before you go. Example: ProV balls spin a lot off the driver. Therefore you would want a shaft that brings the Backspin into the mid 2000 rpm range to maximize your carry and minimize side spin on bad contacts. On the plus side, a Titleist certified fitter will only use quality balls, launch monitor and knowledge to put the best piece of equipment in your hands. And aren't just trying to sell you something you don't need or that won't help your game at a cost of $300 per yard.

Hope this helps.

Luke

The ball the fitter uses makes a little difference. When testing drivers the cover of the ball is not in play, the core is what's important. 

I am a regional fitter for Titleist and tested the difference between an NXT tour (or range balls) and a ProV1x. There was not substantial difference with any of the numbers.

Plus, if the fitter does his job correctly they will take base numbers with your equipment so they can compare to the new stuff.

Good luck.