Are you having a laugh ?
I put Qty in the variation name, a number in the value (1, 5, 10, 25) and the price in the price box set to add this to the variation.
When I try to buy stuff it appears in the cart as for example: IRL540N (10 + ?£8.9) but the checkout price is still the base price. The calculation is just not happening but the variation is showing up.
Try it yourself, Over to you.