I do wish they'd add one lower Championship height with all the other changes they are making. There's already a lot of height changes; one more would not make or break things.
Every other height has an option to bump down the jump height except for tiny dogs.
But...they do? Unless I'm misunderstanding you. My dogs both measure as 22" dogs, but I run them in 16" performance; your dogs both measure as 12" dogs, but you (can) run them in 8" performance. Did they not offer that at your trial? I guess I'm assuming all heights are offered everywhere. Maybe I'm mistaken.
Gusto is pretty much the same as Summer on a different scale currently; he measures 17", so jumps 22" championship, 5" over his withers. I run him 16" performance as I said, partially for the lower height and partially for the lower a-frame. I know a lot of people who use performance just for the a-frame. Some of them even just use the championship height (or higher even).
Not that I'd change things up with Meg at this point, but she still measures into the 22" class, which I think is still a big leap for a 17.75" dog. I know some people who have said that they hear/experience/feel that the performance division is considered the "loser" division, but around here, there is zero judgement about it, and it is often just as competitive or moreso than championship. I wish that attitude extended to all competitions, because the division is such a great option for those of us with dogs who don't easily fit into the championship classes.