The language in Manteno was a little stronger, along the lines that "increasing viscosity does little or nothing to alleviate fuel dilution...the key is the add pack." [sic]More viscosity doesn't alleviate fuel dilution, or impact the rate at which it occurs, it just gives you more buffer to start with.
It may be that, as with oxidative thickening, there is something chemically going on vs mere viscosity changes.
Thoughts of the professors ?