Thanks mia! ^ That sure looks like it would be the Premium Plan T&Cs.

It does not specifically exclude rentals with points or discounts (I believe the T&Cs for the 'free' coverage does have language to this effect). All it says is:

"Coverage is activated when the Cardmember uses an Enrolled Card to pay
the rental fee for the Rental Car and the Cardmember signs the rental
agreement for that Rental Car."

So it comes down to the definition of "rental fee", which is not explicitly defined in the document. I think arguing that rental surcharges constitute part of the rental fee is valid, and since those are paid with the card on my points rental, I would think I'd be covered. I plan on enrolling.