Retro Active Pay Functionality in E1 and Burden/Fringe Calculations

 I am wondering what other users of the Retroactive Pay Functionality in E1 do to capture the union burden/fringe calculations in E1.  Currently when running retroactive pay for a union rate change, the system calculates the associated Group Plan DBA's as of the rate effective with the change, when in fact it should only calculate the difference between the old and the new rate.

For example if I have a Union Benefit that calculated at 3% and should be 3.5% the system is calculating the associated Group Plan at the 3.5% and does not calculate the retro active adjustment at .5%.

How are other clients handling these types of adjustments?