Over time I have noticed that a shaft I use starts out at 12.8 mm and over the course of the past 5 months it is down to 12.72. The purpose for this shaft was to replace an old shaft that was worn down to 12.5. It as well started at 12.8mm. I use a Q Wiz to clean the shaft once a week maybe. I've had the same Q Wiz for more than a year. There is virtually no sandpaper left on the one side. I play quite often. The shafts I've been playing with are the Jacoby hybrid edge shafts. Is this just a thing that happens with low deflection shafts? Does anyone have any knowledge or suggestions for me to prevent this from happening?