Float alone would not recover from the drain down to 12.6v.
I say clearly Full, as acceptance amps are flipping between 0.0 and 0.2 amps at Float voltage, on a 400 ahr bank. Is there any way they could not be Full, with this charge condition?
I still question whether it can handle being plugged in several days per week and if it does well will Gel technology.
Yes, 100% Full is benchmark ed by holding **Absorb** until endAmps.
That Magnum "feature" I think for current purposes, you need to override by rebooting, force a return to the Absorb V Deka gave you, maybe also kludge a long enough AHT if needed.
With Gel being more sensitive to overcharge do ensure you are there - ideally with a known good separate ammeter - to terminate at endAmps and reset the SG to 100%.
Those Magnum "features" are bizarre!
Manually cycle I think, as I said deep enough for a good dozen for purpose of testing SG.
Returning at 12.6V should be with full Absorb voltage.
BTW what specs did Deka give you for Gel, Absorb and endAmps?
Since Magnum is in effect not supporting Floating - which is supposed to only be used to maintain 100% Full
maybe California compliance?
I would try setting Float V to =Absorb
make sure the automated termination whatever you use
maybe reset back to endAmps based?
does not allow overcharging the Gel, use an additional ammeter to verify stopping on time, default to a little earlier (higher endAmps) rather than allowing occasional too-long (lower endAmps) as is fine for FLA.
If they give a range for Absorb V, maybe also use the low end.
But the ideal for all lead is staying Full, letting Float carry loads, even if it means isolating the Gel bank, one way or another I'd try to get back to that no matter what CA or Magnum say.
But all that is not relevant to the testing SG phase.