There is no science in this--and I have none to offer.
That said--I have always avoided mixing brands of oil out of an abundance of caution that the additives could react with each other. Since I have not violated that rule I have no "proof" to offer
"A pessimist sees the difficulty in every opportunity, an optimist sees the opportunity in every difficulty” ---Sir Winston Churchill
"Political extremism involves two prime ingredients: an excessively simple diagnosis of the world's ills, and a conviction that there are identifiable villains back of it all." ---John W. Gardner
“You can’t go back and change the beginning, but you can start where you are and change the ending.” ---C. S. Lewis