Well then that isn't an OHKO. Also, with or without Ink Resistance Up, in order to acquire 10 points of damage you have to be in the enemy ink for quite a bit of time. Definitely more than a second, other wise the Bamboozler would have absolutely no problem one shotting. They have to be in your ink for quite a while, AKA, not happening. It will always be a Two Hit KO, and with that, there is no way I'm choosing the Sloshing Machine over the Vanilla Slosher when I can just Bust Cancel my way through people. It's an interesting weapon, but it has exactly 1 redeemable quality that warrants it being selected over the Vanilla Slosher.
It's Hitbox is wonky as all hell, despite having the Highest Damage output of all Sloshers, it's still a 2HKO, you can't hit things immediately in front of you if you're arcing your shots like you would any other slosher, it's pretty slow, even for a slosher, so that leaves the positive being Splat Bomb and Splat Bomb Rush which is amazing for Spacing. No way is that enough to get me to choose the Sloshing Machine over literally any other Slosher.