Yup.. That about sums it up in a hundred words or less. Echo tunes them to get past C.A.R.B. emission limits.. Then sets the limiter caps to ensure "plausible deniability" , in the event of a warrantee claim, they can deny the claim as the unit will show fuel starvation. They'll blame the claim denial on fuel used, not using fresh fuel, not using stabilizer, not using "their" oil. But, that's not really their fault,, They, like all other manufacturers, are at the mercy of Government regulations. Government says that you can't let the owner tune their own saw.. But they expect the manufacturer to suck up warrantee claims. WTF?
If you get an even small amount of (Ethanol related) build up on the jets, and then you can't dial in a decent tune. You're also running way lean. 'effin nanny state.
Personally, I always tune so that the saw will idle for over a minute, before starting to load up. I know that the slightly rich mixture will give a bit more grunt as it transitions to the high speed jet.
Not to start a "flame war", but that's one of the reasons that I always put a couple of "glugs" of SeaFoam into my Ethanol free Premium fuel mix. If it stops any tarnish from forming on the jets, it's worth it. But then again, I own a few Echos' and not one of them still has the factory limiter caps on it. Keeping the fuel immaculate has also resulted in a "tune it and forget it" philosophy.