Forgive my ignorance in this thread
It's something that's common to EU brands, I've noticed: Tena offers their Slip product in Plus (6/8), Super (7/8), Maxi (8/8) and Ultima (9/8) capacities. (Of note, Ultima is only available in The Netherlands as far as I know, making Maxi the most-absorbent one you can get elsewhere).
I understand why Maxi exists, and to an extent Plus (it's certainly more discrete), but improvements in SAP have made Maxi almost as thin as Plus, and arguably if you're incontinent enough to need a diaper then you might as well go the full 9-yards, why settle for something less absorbent? I'm thinking it might be useful if you suffer from fecal but not bladder incontinence, but I have my doubts as you'd have to pee it in regardless.
Even if there is an adequate use-case for the Plus 6/8 capacity, who buys Super 7/8?
Abena has the same thing: they offer Abri-Form in capacities 1 through 4. I actually have a friend who prefers M3 to M4 and he says it holds about the same, but it's less bulk around his bum and gives him more freedom, but that still raises the question of why M1 and M2 exist. Has anyone tried them?