I have two drivers that are identical (same shaft length, shaft, grip, head ,flex, weight, SW, etc.) The only difference is that 1) one head is 13* and the other is 10, and shafts are installed almost identical (They are w/i 10) into the heads. Yet, I cannot get the same feel out of the 10* that I can out of the 13* one. And the 10* feels stiffer than the 13* when I swing it. The ball comes off the latter hot, but the 10* is only so-so. Besides loft, any thoughts on what is going on? Maybe its loft but given the same wt., etc. I don't think so. Am I wrong? What's going on here?