Charge applied by the modifier is not getting updated when quantity on sales order line is updated -

 Currently a charge (restocking line fee) is getting calculated based on the unit list price where as client wants that it should be calculated based on the unit selling price.

 As our client is not using buckets on the modifiers, we have modified the qp_custom pakage so that it returns the unit selling price of the order line to a formula attached to the modifier. 

THe application method on the modifier is 'LUMPSUM and allow override is checked on the modifier line

 The changes working perfectly when there is no change to the item quantity on the order line. The charge is not getting updated when user is updating the quantity on the order line. I tried ‘Price Line’ and ‘Price Order’ but there is no change in the amount. It showing the values that modifier calculate for the initial quantity entered for the item