This is what you can try in such case: we have processing formula in work center which calculates the total time required. Example - machine time per piece * operation quantity / base quantity. So if it takes 2days and operation qty is 10 and base qty is 1 I need 20days for 10 qty.
You can create your own in customizing by multiplying that factor that means: 2 * machine time per piece * operation quantity / base quantity
This would mean 40days for above 10qty.
You will have to test this in your quality environment. Thereafter you can assign this formula to work center where required.
Regards
Rahul