Need a little help.
Here is the scenario:
We have 2 rebates...
1. Unit wise: Calculated on every bill... if billed certain number of units (say, $5 rebate for each 100 units billed)
2. Volume based: Calculated at the end of the validity... if crosses specific business volume.
If any point of time, the company decides to change the condition value of the rebates...(say, they make $6 for each 100 units billed), it should reflect the whole validity period and take past bills into account. But, it's calculating the bills after the condition value changed with new value and the old calculations remaining same.
Is there any way to get the rebate calculations done for the whole period?