Would you....

Your post made me go searching for confirmation myself because it says there in your quote is completely different from what it has always been. From what I can see your quote is taken from a discussion on a forum page hosted by NGC. Not directly from the NGC website.

That said, for years NGC had the various definitions for their special designations posted on the their website, like this one -

https://www.ngccoin.com/news/article/792/

But I looked and looked and can no longer find one for Full Split Bands on Mercury dimes. This is the best I can find, a quote from David Lange -

"The designation FB follows the grade for coins having fully split and raised bands." that comes from this article.

https://www.ngccoin.com/coin-grading-guide/Grading-Mercury-Dimes.aspx

But there is a lot of other stuff that discusses it posted on their forum pages and other various articles. And that stuff is all over the map. It talks about the upper and lower bands, just the middle bands, and all 3 sets of bands. But there is no longer a specific definition like the one for Full Torch that I linked to above.

So all I can tell you is the definition I posted earlier is the way it's always been. But anymore, who knows.