Can User select VAT?

[bettinz]

Hello,
I've a curious question, and I hope you can help me.
I've an commerce with products, and VAT 22% (I'm writing from Italy).
So far, so good. Now, a user can ask a facilitated VAT (10%) on some products.
I need users can check a box if they want facilitated VAT on particular product, so they can complete orders with different Vat. Is that possible?

Thank you

Edit: I can Use Custom Fields on product, but It doesn't work on %, right? So, for example:
Net price: 1000€
VAT 22%: 1220€
Facilitated VAT 10%: 1100€

Can I add a custom fileld for arithmetic operations? Like VAT22-(NET*0,12)

Edit 2: Can user select vat in checkout? For example, in tax rate I've
VAT 22% and VAT 10%, but they works at same time, I can't permit a user to select one or another one