Not that I care about blends too much and that's probably why I've never posted this before, but... Way back in the days when Syth-blends were coming out (1993?) I called one of the oil companies to find out what the difference was between these and synthetics. I was told that they were NOT simply 'a mix' of dino and synth, but a completely new oil formula altogether. ie. you couldn't make your own 'semi-synth'. True or was I being fed a line??