Hi, I have a Stringway ML100 with the Concorde base, but whenever I pull tension on the mains from the throat when the racquet is in the 'up' position, the base actually shifts upwards on the shaft that supports it while I am applying tension. This causes the racquet handle to drop onto the top of the tension head. I don't believe this is how it's supposed to work. Is there a way to 'lock' the base so that this shifting doesn't happen? Does this make any sense??