That's my take on it, as well...the oil thickening has got to affect the mds functionality in some way, but I really have no idea. The only catch I can think of where it may not apply as directly as we suspect is that the "thickening" isn't the typical kind of change that we liken to a viscosity change. It's more like a long-chain polymer "gooyiness" (a stringiness that fills the air space tolerances vs. fluid thickness with actual shear properties), rather than an actual change in viscosity (which I gather is the critical element that affects the mds lifters). I could be wrong on all of that, though. I was just curious if anyone has ever tried it.
Its really designed for diesels. The tolerances are much more liberal to heavy oil. The polymer in it is designed to "stick" to bearings to prevent dry start in diesels because they run at 18:1+ compression ratio and are brutal at start up