Yes. I believe too much twist makes a difference in the performance of a bow! If your not sure, try it, make one up a little longer, and shoot it, you will feel it in the shot. Vibration and side to side ocilation, you bet.
Last summer, I shot a very fine made selfbow, beautiful tiller, great early draw tension, and the shot, horrible. Just shouldn't be. I looked the string over, unstrung, and unwound a portion, way too much twist.
Think of it this way, if your twisting it up alot, your using more material, = more unwanted string weight. This is the trick of doing good flemish strings! And why some prefer to do only endless.
Terry Green said on a post awhile back, to Jerry Hill about a dacron and High performance string shootin about on Par as for speed. After reading I wondered if the HP string was built with too much twist, probably.
For the folks who build their own, and complain of too much creep, probably too much twist!
Now, not saying you can't shoot with it, you can, and you will adjust to the cast and performance, but it could be awhole lot better!
Another thing I have seen from folks who give you a string measurement, say 55" and you make to the specs, but they say it came up short. If the string they measured off of had too much twist, and when braced, will stretch considerably more, so the big difference in length. My 25+ years of twisting, experience.