......by my understanding, the grades are an accepted standard within the coin collecting community.

He knows exactly what he wants to buy, and the grader has verified the condition of the coin to his satisfaction.

It makes sense to me.

I also asked him about the very issue you raised. I said "don't sellers just keep on resubmitting coins until they get a desired grade?" He said, in summation, that with the two grading services he relies on (he said he only purchases coins graded by two services-I didn't aski which), that can and does happen, but generally, the coin will be returned with the same grade, and the seller is out the price of resubmitting the coin. He said it was the exception, not the rule.