The 13.5° and 15° are tipped at 1/2" and  the 19° is tipped at 1.5" so it will play a bit stiffer when you move the shorter shaft into the 3 wood.

There is also going to be a swingweight difference of ~6 points because of the shaft length.   This can be compensated for by a lighter grip (such as Winn Lite Dri Tac - that is available at Titleist).   Concur with Cathi on the stiffness.  It may play like stiff +.

The length of shaft will affect solidness of contact ( shorter shafts are usually easier to control and produce more consistent on-center hits) but not always -- need to be fitted for that.  Shorter length shafts DO NOT cause a loss of distance nearly as much as an off-center hit will.

 swing weight has been proven to not have a significant affect on ball flight.  It is feel preference and therefore a decision of the player not neccessarily a fitting issue.

Thanks, Steve.  There's nothing left for me to do but to give it a try.  That's a great thing about the 910 and 913 series it doesn't cost anything to give it a try.  If too stiff I could also cut the 3W shaft by 1/2" and see how it feels.  Just didn't want to cut it if the 5W shaft works.

@ Jerry -   I have the 910F 19* set to a shaft length of 41" and Surefit setting of D3, a 910H 21* set to a shaft length of 39" and Surefit at D3, and a 910H 27* set to a shaft length of 38.5" and Surefit at C3.  The first two clubs have Winn Lite Dri Tac grips and the 27 has a Winn Excel RF grip.  An Excel RF will restore the swingweight by 2 points vs a 52g rubber grip (you lose 3 swingweight points when you shorten a club 1/2").   

Agreed it is a feel thing and, quite honestly, a lot of golfers can't feel a difference of 2-3 swing weight points. I've played clubs with a swingweight range between C8 and D5 (I had a couple steel shafted fairways and hybrids that I actually tamed the swingweight down to D4 by going from an Excel RF midsize to Golf Pride Tour Wrap Midsize - 43g to 67 - 5 swingweight points!).  Also, you've probably seen some demos where the distance gained between a 46 inch driver and a 44.5 inch driver amounted to about 2 yards or so.

I have a SM c-c 50-08 that I have cut down from 35.5" to 35.25" and it hits better that way.  I find it easier to pick the ball clean on a tight lie and it also does well on a long bunker shot in somewhat soft sand.