The other variable is the difference in the exchange rate (for non-Americans in the US) between the charge and the refund - the bank's "buy" and "sell" rates, plus any commission charged by the credit card company. In the example given that amount was basically the saving between the Senior and Flexible rates, with the latter having none of this nonsense. With the amount charged more than double the nightly rate, a refund of some amount was going to be necessary, rendering the Senior rate fairly useless. I booked on points.