PV solar system charging voltage low

[FloridaFlyer86]

Ok solar gurus - I am experiencing low voltage with my PV solar system. The charging voltage will not go above 12.8V. I'm using a Morningstar SS-6L-12V SunSaver controller (2nd gen) with 4 new Crown 6V 220 AH batteries wired series/parallel for a 440 AH 12V system, and a single 95 watt PV panel (astroenergy). The measured open circuit voltage from the panel is 20.3V. The SS-6L-12V should be charging at 14.4 volts for flooded batteries. The green charging light is on. I’m using a TriMetric TM-2025-RV battery monitor and I do get positive current flow (5A) but I’m going to end up stratifying my batteries if I don’t get the voltage up. I also have measured the voltage at the terminals of the controller and also see 12.8V there. (at rest battery voltage is 12.5V.) This is a new system (so all connections are new and clean, with dielectric grease and proper torque) but the components have been used before… over a year ago so my memory is hazy but I’m pretty sure I saw 14.4V before. I’m not too concerned about any wiring being undersized, I went overkill to avoid that possibility.
So I have an email in to Morningstar but I have no idea how long they might take to respond… and I might just have something stupid going on, unrelated to the controller. Any help is appreciated, hopefully I haven’t left anything out.

[NinerBikes]

Rough rule of thumb, for every AH you have at 12V, you need at least 1 to 1.5 watts of solar panel to charge it. Since you have 440AH in storage capacity in your batteries, you'll need about 440 to 660 watts of solar panel to get the job done.

[pugslyyy]

I think you are asking too much from that single 95 Watt panel. 5 Amps is about right, so in perfect conditions you might get 50Ah per day from it. That's just a drop in the bucket for that 440Ah of storage you have.

[BFL13]

You need a lot more than 5 amps to raise the voltage on four low batts anytime soon. Not enough daylight time in a day.

Or if they are not that low, perhaps there is a draw on them while you are trying to charge them at the same time?