Does anyone know the differences between these PT F tubas?

[tmmcas1]

My understanding was that the PT11 was the 6 valve version of the PT10. 5 and 6 on the left hand. When the big merger happened I think they went away from all the PT classifications. Maybe that’s incorrect. I only know this because I had to do a little digging to figure out what they call a PT9 now (it’s a 3100) when I wanted to try one. I was told the PT8 and PT11 were rare. Maybe a Buffet person or Mr. Tucci will chime in. It’s confusing.

Tom

[tmmcas1]

Clearly I know nothing...except that a PT9 is now a 3100.