910 D3 vs 913 D3

I was recently fitted for a 913 D3 9.5 stiff ahina shafted driver.  the person who did my fitting at Roger Dunns is also my playing partner a former mini tour player who I trus completely.  he plays a 910 D3 withe the exact same shaft and set up down to the grip.  we played this week end and switched drivers on a few holes I was consistently longer 15-20 yards with the 910 and he was shorter by 10-15 yards with the 913.  has anyone had these results and can anyone shed light on this for me? 

I personally don't have any experience with the "being fit" part of the 913 but was fit for the 910.  Earlier this year I swapped out the 910 head for the 913 and just never saw the difference. It was just some on course testing where I usually hit the ball   It was definitely shorter for me.  Maybe another shaft might have made the difference.  I was gaming a project x

Steve; I must say that all this back and forth on which driver is better (910 vs 913) is about to wear me out. I have a 910D2 now and going to get fit for a 913D2 on Friday, so my problem is that I've only had my 910 about 6 mons. now and I would go for the 913 if it was better than my 910. I've read all the threads on TT discussions, and some say no differance, some say the 910 is better, and some say 913 is much better. The only complaint I have with my 910D2 is that the sweet spot is so small. If I don't hit the ball dead center of the club face then I've missed the sweet spot. I've heard that the 913 has a bigger sweet spot, so maybe I'll find out on Friday.

I was recently in Dubai on holiday and got a chance to test the 913D2 with Trackman. I currently game a 910D2 10.5deg Motore F1 and putting this shaft in a 913D2 head gave me the same numbers as my current 910D2. So, for me there was no need to change to the new 913D2. With regards to feel they are very similar, but I really liked the sound of the 913D2. Still, I will keep the 910D2 for now.