Yeah, I'd have expected the HPL to held up better, considering how much it costs.
See if HPL can whip you up some no-VII 40.
Or, run Valvoline VR1 SAE40, if it doesn't bother you that it's a non-synthetic, non-MC specific oil. You'll never have to worry about shear. My bike loves the stuff. Currently $40/6 qts on Bezos Express.