Grade B Picasso Clowns?

[GreenSpottedPuffer]

What does this mean? J&L has "Grade B" Picasso Clowns right now. They don't have nearly as much black as the ones I have seen in pics though. Does Grade B just mean what it sounds like...they aren't as nice looking?

Also, I know these guys are basically a color mistake that has been breed OVER AND OVER again...aren't they starting to get kind of inbred by now?

Do they live as long? Are they not technically a genetic mistake and maybe even not the 'strongest' fish?