Ho to input "Discount/markup" NOT as %, but as a number instead ... ?

Hello Eugene.

Excuse me but, may I ask You ... would not be possible to add a way of insert Discount/markup NOT as % but just as a number? I do not know if it is common or not, but in my case, I use % very often, and I would need, at the same way, to just write a normal number instead ...

Let's say I want just to remove 250 ruble from this small amount ... why should I calculate a %? I don't know if it is possible. But I had to ask ...

Thank You a lot!

Pietro