HTHS is a means of comparing oils of same viscosity when in the performance area, greater film strength at same oil temp, or dropping viscosity giving greater flow but maintaing film strength.
Porsche specify 3.6 or above.
As far as I know
MoS2 is a suspended, non-soluble micro-powder. As such it can settle out in storage when used as an additive in motor oil. However, MoDTC is a fully oil soluble salt, will not settle out in storage, and, in solution, passes freely through the oil filter. (Since it's in solution, it can't "clump".) However, heat and pressure (of which there's plenty inside an operating engine at points of sliding metal-to-metal "contact") will allow the molybdenum to be deposited and "fused" with those sliding metal surfaces as an anti-wear, last-line-of-defense, extreme pressure agent micro-coating in the event the oil film is briefly disrupted.