An F1 to an F1B, I believe is an F2...but beyond the grade changes that are simple, I am at a loss too. They keep changing them!
ALAA (previously LAA and ILA) have come up with a new system signifying whether the dog is from an Aussie line or American and when it is bred back to a parent line, it also tells that...but I have not had the time to study the new code and I only breed F1Bs so at this time, I don't worry about it much.
I think some just make it up as they go :lol: but I do know if you take an F1B and breed to say an F5 you get an F3 that is what Tejas is. But if you bred a Poodle to an F5 they are ALF5P's since you bred back to the Parent breed. They have allocated 9 places you can bred the Poodle in back you can only do it 4 times you use the 1st 2nd in the very beginning so then you just have to watch and breed back the poodle when you think you need to correct a coat in the puppies. Hope that helps it is very confusing sometimes. :?