Batch specific UOM - Inventory correction factor calculation custom

I have used the functionality of Batch Specific UOM during procurement. It is working fine. Inventory correction factor is getting calculated proportionally based on formula

(Variance in Prop. Qty / Expected Prop. Qty) * 100

We have requirement to reduce the inventory at a given rate as mentioned below

80 and above - 100% payment

70 to 80 - reduce Rs.10 per Batch UOM less (i.e. if 77 means 10*3 will be reduction, 79 means 10*1 will be reduction)

Below 70 - complete rejection of materials (No issues. Can be achieved using rejecting lot)

How to achieve Inventory Correction Factor determination for slab 70 to 80 as mentioned above.

I also tried Info record with scales and price control 5. Not working.

Request your help in this regard