The Schumachers are well known to go to too high a voltage, whenever it dang well pleases them to do so. Other times it drops to float voltage well before the battery would like.
My SC2500a shoots to 16.4v at a constant 15 or 25 amps, skipping the constant voltage stage at the high 14's and just beats the F out of the battery.
While sometimes 16v is required on a heavily cycled bank that was not brought up to 100% often enough, 16v is NOT required each and every recharge.
I know you are charging 6v's but just halve these numbers.
Unless your batteries are in need of an Equalization, I would not let that Schumacher loose on them.
My Sc2500a is disassembled, in a paper bag. I do not trust it to leave it unattended on any battery I care about. I am hoping some thicker DC output cabling might tame down its neurotic proclivities. I would like to have a 'lender' charger. They are not getting my Meanwell.
The voltage potentiometer would make their head explode as it would seem to do to some people here who have complete faith in 'automatic' blinking and soothing green lights