I bought two new 913 clubs, fairway wood and hybrid. Previously I have four Titleist 910 clubs, driver, fairway wood and few hybrids, and also few extra shafts. I assumed that shafts are compatible with each other, but these were not. Is it realy true that 910 and 913 shafts are a bit different and these can't be interchanged. If it is so I am very disappointed.