Well, if the friction coefficient is higher for the disc's material, it'll increase clamping capability,
but that estimate is sometimes overinflated, and also refers to a new pressure plate being used, not an old one.
I have a six puck sprung hub with a stock PP and it slips a bit. Going to be buying a Spec 2+ soon.
If you're looking for a true increase in clamping force, you're right- get a higher load pressure plate, and get a
full-face disc; stronger and smoother.