Collecting Taking card out of wrapper for better grade/price?


Aspiring Trainer
Hi, I've been planning on sending off a promo card I have to be graded. It's currently still in its clear plastic wrapper. I took it to a local card dealer to get it looked at, and they mentioned that I actually would want to take it out of the wrapper before I send it in to get graded - my guess is because the wrapper makes it hard to see the interior card, and so they have to grade more off of the wrapper, which I think has some issues. I wanted to get a second opinion before taking it out - is this a known thing?