Two possibilities. Did you set the tension correctly on the drop weight bar? Normally, 17 ga strings are set to a lower reference tension than 16 ga strings when using drop weight machines. The second possibility, assuming the reference tension is correct, is what were the settings input into RacquetTune? Rip Control is not a poly, and not a Syn Gut. It's a weird one, so you need to set the factors correctly to obtain good readings.
BTW, even with drop weights, you should be much closer than 5-7 lbs if you measure the racquet right after you take it off the machine.