RE: CALLING ALL "TAURUS" OWNERS.
Nothing strange about the rpm differences between props at all. The TF props flex more than a trampoline, causing a signigicant loss of efficiency. That's way those things are made with the prop blade curved to the back. They flex a long ways forward. Individual engine tuning plays a large part in rpm counts as well. Those that know how to tune an engine will always obtain more rpm than those that don't. Differnt manufacturers make different props from the other manufacturer, providing significant differences in propeller performance. I found that a Menz 22-8 beats the Xoar to death in rpm, but an MSC 22-8 at lower rpm beat Xoar and Menx in all actual flight performance parameters.
BTW, constant pitch props typically provide a higher rpm level if max rpm is what you seek.