Hmmmm....
Dolmar will waranty thier product(Known quantity) running thier oil(Known quantity) at 100:1, But others(unknown quntity) only if run at 50:1.
So I would assume some Dolmar dudes in Lab Coats tested some stuff, and then told the guys in the 3pc. suits who write the manuals what happened.
BINGO!! As tolerences grow with use, some other oils at 100:1 do not provide enough cushion or some such, and they cannot go making statements about others oils.
So..... who's other oils do and don't?
Meh.
Run anything other than Dolmar oil at 50:1 in the saw.
Might cost ya an extra 20 bucks a year if ya run the snot outta the saw, but it's cheaper than the Kleenex you'll need from crying over a fried saw that ain't covered under warranty.
Just my .02 and barnyard logic.
Stay safe!
Dingeryote