I came across an eBay listing showing a 16 subject sheet graded and encapsulated by PMG, but I read in an article that only uncut pairs of three and four subject sheets are eligible. I rarely see notes of 16 subject graded, so it had me wondering if they're eligible. The US Mint states that notes are 312mm x 538mm but according to PMG services, neither the oversized and custom holder support this. Which begs the question, how was the note on the eBay listing graded? Does it have to do with special factors such as the serial number?