If car companies are so anxious to promote their cars as not expensive to run and maintain, then if running on a lower octane is so harmless why would they not write in their literature that low octanes is useable?

Mercedes has fill for life transmissions, would a shortened life of a catalytic converter be the only reason premium gas is recommended by Mercedes?

Maybe to pass emissions Mercedes needs to run premium, carbon deposites, detonation not manageable by timing management.

Lots of questions.