Income recognition - pro rata basis

Yes let me give you and example of customer receiving a discount voucher if you enter into option contract.

Product soap sold at hundred inr

Discount voucher given 20 inr

Total one twenty is the cost to company

We have to allocate this on a prorate basis

Product soap sold at (hundred/one twenty into hundred) = eighty three

Discount voucher actually costed (twenty by one twenty into hundred)  = 16.66

Total cost of soap is 83+16.33= 100.

That's pro rata!

If the company wishes, this discount can be unwinded on other products.

I gave you an example right? That's only calculation anyone has.