Medium heat cooking is amazing. My food tastes better, it's easier to catch the food exactly at "done", and I can walk away from the pan for a moment if duty calls. BUT, since you do not appreciate these benefits and just want your food sometime before the next stone age, use the oils with higher smoking points to be safe. I cook my eggs this way when I make them over-easy. Any cooler than medium-high and they don't really set correctly. But salmon, anything above medium turns it to rubber.
Here's my take:
A healthy body can easily neutralize the oxidized particles from a little over-heated oil once in awhile, but I wouldn't cook your oil to smoking for an extended period of time daily. If you're just flash-frying something like bacon, then you've got that short time duration on your side. It takes longer to oxidize the oil than is does to cook your food. That said, just using healthy oils like tallow and coconut oil already put you miles ahead of the game, so if slightly overcooked oil is part of your 20%, then the rest should counterbalance it.