I am renting a car with Avis in the US for 4 weeks, as a UK traveller.

On my booking it says "Covered for loss or damage
You're covered for accidental damage, but if any repairs are required an excess may apply. When you collect your vehicle ask at the counter about how you can significantly reduce the excess.This vehicle's excess is 0.0."

0? But it also states that an excess may apply if repairs are required.

Going through the booking process again as I reserved my car back in November, I can see:

Excesses:
0.00 DAMAGE EXCESS
USD 0.00 THEFT EXCESS

"You're insured for damage. If any repairs are required, you'll need to pay an excess fee to cover them."

So what can I expect for repairs?

I am trying to decide whether or not to take out third party excess cover.

Even the 0 sounds odd, whenever I have rented a car in the past there has been a hold on my card for an excess, although this is my first time renting with Avis.