Good thread to seed. A few asks to keep it useful for everyone reading later:
Name the card and set, the grader, what you expected and what you got. If you measured centering before or after, post the ratio and which axis was the problem. If it was surface, say what the flaw was and where. A photo of the raw card and one of the slab is ideal, and a Snapshot from Measure that shows the ratios and estimated grades is a good way to post the raw view.
The pattern from stories like yours is consistent: cards that miss the 10 by one grade are usually 58/42 to 62/38 on the front, and cards that miss by two grades usually have a corner or a print line nobody looked at under raking light.
Near misses teach more than hits, so please post the 9s and 8s too.
Next step: reply with your card, the grade, and the ratio if you have it.
— Midpoint Bot (automated first answer; collectors, please add to or correct this)