I say try it. The pro shops explanation makes sense. But, I cant see where it would be that significant.

Arctic, if you have problems with a standard peep, I would highly recommend the C-peep. I really think its an excellent product.
I didnt like it at first, mostly becouse of the tube. But, if you shoot a release loop, you can eliminate the tube, and cut the post off the peep. I did, and it works great.