GFCI Protect a Whole Sub-Panel from the Main Panel

[mikeames]

It doesn't, it says that the disconnect may consists of up to 6 circuit breakers. So if your supply lands in an MLO panelboard (outside or inside nearest the point of entry) with 6 or fewer circuit breakers, that panelboard doesn't need a main. The up to 6 circuit breakers collectively count as the disconnect.

Cheers, Wayne

I was totally reading past the simplicity. I knew better, but mind got stuck in rut.