[pbhjpbhj]

Do you know why? It might seem obvious, but corporate users for example who want to support development often can buy a product that they couldn't donate to -- so greater income doesn't necessarily show that people more likely to pay prefer Windows Store, that might just be the easiest way to pay.

Tax for independent purchasers can change the way one will pay -- like if you're a UK charity I can donate and get you Gift Aid (if you use the scheme; a government increase in the money you get), or purchase and show it as a deduction in my taxes.

Obviously you know your users better than I, but I wonder if you've surveyed/canvassed to understand their motivations?