The points came from the room bit on my statement:

Radisson Blu Plaza Hotel, Oslo | Room Earning 20 Points per USD 3,198

Rate shown when booked was inclusive, no breakdown of the tax.

That said, on my bill, most of the room charge seems to be at 8% VAT, and some at 25% VAT. It does seem to be based on the pre-tax amount.

Thanks for the help.