I try not to get too hold up on yeald numbers, from grow to grow, as my enviroment also changes around the year. Can't keep the same night temps at winter, and during summer we stuggle with heat.
Cutting a little early, can also play a big factor IME. But we have to do, what we have to do sometime. But in the end as long it's good weed, and there is enough to cover the needs till next harvest.