By default the Compensation Tool will always calculate proportional value (PV) based on the actual point total of the applicable female Job Class.  If you require PV to be calculated from the midpoint of the band simply check the associated radio button in the Banding table in the "Calculate PV from Midpoint" or within the banding details page.

When selecting to calculate from the midpoint the Compensation Tool will update the Pay Equity analysis for all jobs for all years requiring PV.  

The Compensation Tool will not allow you to calculate from midpoint and actual point value within the same project as this is perceived as non-compliant as this method would appear to be manipulating results.