Anyone else ever have this happen?

Recently, I won a coin at auction on Ebay, a fine example of a proof Mercury dime. Specifically, a 1940 proof Mercury dime graded Proof-67 (PF67) by NGC which is pictured below.

However, when you enter the certification number (1867064-001) into the "Cert Lookup" on the Collector's Society website, it only garners a Proof-66 (PF66). As you can imagine with many coins where one grade point can be the difference in 100's to 100,000's of dollars, there seems to be a descrepency in grade. In this coin, the difference in grade in cost was about $200 and my bid was low but I was most concerned with the number of points for a PF66 was almost 500 lower than a PF67.

I ended up calling NGC about the issue and they were very cooperative in addressing this. I sent the coin to NGC and they agreed that it should be a PF67 and they will update the registry to reflect that (which has not happened as of this writing since it was just settled this morning). In fact, they even agreed to re-holder the coin since it had some scuffs on it. NGC had no obligation to do that.

Has anyone else had to deal with an issue like this? My guess is that someone "fat-fingered" the grade into the Registry database.