I see, thank you for explaining.Higher OXPHOS only increases ROS production significantly in an electromagnetically polluted environment. The incoherent EMF causes electrons to leak from the electron transport chain, which is what creates the ROS, which then in turn damage parts of the cell and lead to a buildup of damaged cell constituents that then burden the cytochrome P450 enzymes needed to get retinoic acid ready for excretion.
Personally, even if there is some physiological use for very small amounts of VA, I doubt that there is a such thing as "using up" any significant quantity other than in the sense of detoxification and excretion.
I'll read about vit A some more.