Although thats fairly acurate at what would be going on. But the thing you missed, is these breeders dont work in 1's. Especially when it comes to making new morphs. I imagine the first desert was paired with multiple females, the very first year he was ready to breed.
So theres 3 years between your 7th year and the 10 year mark we are at right?
Anything produced before that 7th year, should be more then good to go, male or female. Assuming people hold some males and females back, They should have been able to hit a super or even get some clutches from a desert female. There are quite a few deserts out there... Its not like we are lacking in that deparment, its the info that follows.