Excess vermiculite

Just had a liner put in our inground pool. It is a 19 x 36 Roman. After filling we noticed the incline edge from the shallow to the deep end was very rounded. Our PB told us when then came back to cut out the hole for the light that they could trowel this out. Is that possible? He also said if they couldn't trowel it out they would come back after the season, drain the water, fix the problem, and pay to refill the pool.
I haven't paid the balance of my bill yet. Should I get all this in writing and pay the bill?

I wouldn't.

It's generally a bad idea to pay 100% for work that's not 100% finished. I'd make a reasonable payment, based on the completion. If you are about to make a payment, leave unpaid a portion for the light and the leveling, based on the assumption that it will be the complex fix in the fall. Then pay for completion as it occurs.

But . . . it's Ohio. It's cold. Why don't you postpone pool opening and have him fix it now? That way, it's not hanging over your head or his.