This may reveal yet another area of my ignorance, but I don't know of any reason why the power at the mid-PTO would be any different from the rear PTO. Since the RPM, at any given engine speed, is generally higher for the mid PTO, the gearing is obviously different so that torque, in turn, is different. But the result of lower torque and higher RPM should yield the same power.
Maybe someone who actually knows will tell us; --am I wrong on this???