Marks & Erasures

[Bliggity]

I'm looking at a T card that is currently sitting in a SGC 20/1.5 holder due to initials written in pencil on the back of the card. The card otherwise presents very nicely and would probably grade 4(MK) by PSA. I plan to hold onto the card and would probably "liberate" it and erase the initials just for my own preference in looking at it regularly, assuming I could do so with no paper loss.

BUT...if I decide to sell it later, what effect would the erasure have on its ability to grade? Is that an automatic "A" from SGC and PSA? If the resale value were to take a substantial hit with an erasure as opposed to leaving the writing in place, I'd probably just leave it.

Thanks!