It is not your voltage causing your problems it is the lack of time spent at those voltages that is causing your issues. VERY, VERY common issue and easy to solve.

I would recommend keeping it at 14.4V to 14.6V but extend bulk and absorption times in the advanced/custom settings. The universal factory programs on these regs are quite lame. You get about 72 minutes at an absorption voltage (36 at bulk voltage and 36 minutes at absorption) by using the pre-set "lawyer safe" factory settings. 72 minutes for most banks is totally inadequate... They go into float far too early unless you physically program them not to. IME there are very, very few boats out there that can use any of the factory programs and get sufficient charging.

A simple trip into the advanced/custom program settings will allow you to extend the bulk time and absorption times. The simple answer is that your reg is going into float before the bank is actually charged. You should be getting down to about 2.5-3% acceptance at 14.6V before you enter into float (less than 2% at 14.4V) but with 30A of acceptance at 14.6V you are simply not getting full before the reg drops the voltage. Drop the voltage you drop the accepted current because at 13.XX volts the bank can only take so much. Dropping the voltage before hitting 97-98% SOC, at a proper absorption voltage, and you greatly extend your charge times to full...

You can easily fix this by holding your existing voltage for a longer duration. On the MC-612 you can go into advanced programming and simply change the B1c (bulk time) and A1c (absorption time). I would run both out to at least 3 hours and see how that goes.. You can also adjust the voltages with the Bu (bulk) and Au (absorption) settings. You might even program it for 3 hours at 14.6V then a drop down to 3 hours at 14.4V...

"Premature floatulation" is a problem I fix regularly with Balmar regs and it is simple to do in the advanced programing mode. Advanced programming should be used on nearly ALL Balmar regulator installations.