I can't stress this enough: grading can be subjective, especially when all dealers do not adhere to a common definition scale.
For instance, except for one dealer, everyone I know uses a C rating scale that goes from Poor to Near Mint. The one dealer who does not adhere to this scale has a proprietary scale that tops out at Fine, like book sellers do.
Everyone except for one dealer uses common terms to describe folded or rolled posters. One dealer calls rolled posters 'unfolded' which almost every other dealer says is incorrect, because that definition indicates an item was previously folded and is now rolled. A poster that has never been folded, cannot properly be described as unfolded by any dictionary definition. It is an incorrect description.
So with such disparities, it creates wildly varying specifications and until all dealers adopt a singular scale, such as have comic books, baseball cards, coins, stamps, book sellers etc, there will never be a time that everyone can mutually agree with anything.
Of course, there is a solution, which is that we all post grading definition scales on our websites to help the buyers decipher our meanings. That way, even with varying scales to some degree we can make a collector aware of what they can expect when they actually get our merchandise delivered.
Like T, I am curious to see pics of the poster in question