I was going to say that the guy probably didn't realize that carbon express arrow numbers don't correspond to the amount of deflection or spline, but after seeing that you are only getting deflection of .324" and .391", I would have to agree that you are more than likely over-splined. I would think you need something in the .400-.500" range, maybe even more.
That being said there's many factors that make up the right arrow for the bow/shooter. Adding more weight to the tip, shooting a longer arrow, or a longer draw length, will effectively increase the deflection of the arrow, and you may be able to make those arrows work. The best way to tell for sure is to bare shaft test your arrows.