Go ahead and pay double for Stihl oil if you want. I've always run the cheapest bar oil I could find, and as far as I can tell it all works fine.
Stihl two stroke oil is Jaso FB garbage too, don't run that either. It's not just overpriced, it's objectively much worse oil than others on the market.
What he said ^
That is a tough sell but it's true. Coolaide drinkers say otherwise so I'll leave it there.
They do still use a package additive far below any FD rating in fact it won't make FC in an orange bottle. Remember now this is factory recommend over any other redarmour type oil from another place. It's really good for low carbon, no deposits and clean spark plugs