They have HTHS in datasheetAMSOIL SS also uses API compliant levels of additives, as can be easily gleaned from the chart.
Nothing from these carefully selected comparisons tells us that the oil is better than AMSOIL SS. HTHS is also omitted from the PDS info, which is interesting, but not surprising.
What are you expecting UOA's to show you?
it's 3.8 for HPS 5W30, and I used the PDF from their current webpage link.
If we have enough UOA, then we can compare the oxidations at x-miles on engine-y vs the VOA. The more delta the more oxidation? Lets say I have N UOA on each oil same engine-y and x-mile, we should be able to make some conclusions. Now, if we want to be within 5% p-value we might need many UOAs (large N).