Well, you should try recalibrating your expression pedal.  You can do this either in H9 Control under Pedal Settings or on your TimeFactor itself in system mode.  Basically, you'll want to make your TimeFactor forget its current calibration settings by turning pedal calibration to off and on again.  Then, you'll want to move your expression pedal from heel to toe so that the TimeFactor learns the pedals calibration, and then, you'll want to turn pedal calibration off to lock out any further changes.

The TimeFactor user guide explains how to get to this setting on page 52:  TimeFactor user guide.