Lol, I don't remember my biochem classes as they were likely before you were born. My biochem prof was f*cking brilliant; too bad I was such a poor student. But, I agree with you -- it wasn't the amount of esters to which I was referring, and in fact it was Motul's explanation, not mine. There was some reference in some Motul literature that referenced the second ester (current 300V is a double ester formula, but IIRC, the former 300V was a single ester) having a polarity that improved its adherence.Fair enough, yeah I should clarify that 300v is omitted from the compatibility tables, not outright excluded. I do have a degree in biochemistry, and I can say with a fair degree of confidence that the amount of esters present has very little to do with polarity.