Some folks don't like Amsoil's marketing, but the products I've used seem to be very high quality.
Not chainsaws, but an example. Evinrude sells xd30, xd50, xd100 oil than can be used in ETEC outboards. If you use the 100 exclusively you can take the outboard to the dealer and they will change the oil injection system to use less oil. Amsoil just approved their HP for use at the xd 100 setting. I thought about it, but no thanks. I use the HP Amsoil but at the regular setting in my fishing rig.
Amsoil used to sell littlle packets of Sabre to mix with 1 gallon of gas. The packets contained 1.5 ounces of oil, which is 85 to 1. When you are dealing with tenths of an ounce of oil, I think it would be easy to get say, 120 to 1 if a minute amount of oil stuck to your measuring container or your eyeball was off that day.
Long story short, the folks who are telling you to go ahead and run it but at a ratio closer to 50 to 1 are giving you good advice.