I don't think voltage settings work at all. Just use the power limit slider. With AORUS Gigabte 1080 Ti's I can go as low as 150 watts (50% power limit). But that's too low.
When I talk about voltage with Pascal cards, I mean controlling it with curve in MSI AB. It definitely works, that's how I adjust all my cards. Although there's a chance that with setting PL to 50% the voltage could go even lower than 0.8V? What's the actual gpu voltage on your Aorus cards when your consumption goes to 150W?
Oh yeah, the curve method works, you're right but 800mV is too high for the lowest end unfortunately.
Looking at only one of my rigs, for 50% PL I get anywhere between 0.7620V to 0.7930V depending on the card (each card has it's more or less stable preference for the same clocks. something something, ASIC quality). Same figures for 3 different algos.