Blends are all Dino Oil far as I know,, Some highly refined, some not regular,, Or more than likely all "Medium highly refined".
Some myths about Synthetics and the fact behind them.
"If you switch, you can't ever go back" Well, for a very short time there was one synthetic (NOT Mobile's) that did indeed cause issues if you switched back, but today.. Well... I'm lubed with "Durablend" which is one of those blends.. If you can blend 'em, you can clearly switch back.
"It will eat your seals" Again an early formula did that, NO longer in production, Modern synthetics are seal friendly.
But for some reasons, the "Warnings" which no longer apply keep hanging on.