Yes, I know how computer evaluations work. The fact that they take positional as well as material considerations into play doesn't change the point, which is that playing a +5 sure-win move instead of a +8 sure-win move is not a horrific magnitude-3 blunder the way that playing a -2 move instead of a +1 move is, whatever your units of magnitude are, because what really matters is the change in the expected result of the game.