Shady Insurance Agent?

Suppose your deductible is $1500 and you have $500 worth of damages(unknown to you yet). You let insurance company book the service, and opt out of a rental car. How much do you have to pay out of pocket? My agent suggested if the insurance company just booked the diagnostic appointment, I have to pay $1500 even though the damages turn out to be $500. Who do I pay the extra to? I asked for clarification and he started talking about rental cars, changing the subject.

He really wanted me to do a "photo estimate" first to see whether or not the damages were $1500.

I'm thinking, why don't I just take it in and have stuff fixed, they cover anything over $1500. I thought that's how deductibles work. He's saying that's not the case.

Then he fails to send me the link for the photo estimate.