Considering VMax V6-225 6Volts 225AH Batteries

Am hoping for some TAB forum wisdom. Apologies if this has been discussed previously and I have missed it.  
I have read in some posts that the WFCO 8735 power center (in my 320s) maybe unable to full charge AGM batteries.  Has anyone experienced this?   If this is the case, is it specific to VMax brand or all AGM batteries? 
WFCO states regarding charging - Automatic three-stage charging extends the life of your battery with output voltage modes of 13.2 Vdc “float” mode, 13.6 Vdc “absorption” mode, and a 14.4 Vdc “bulk” charge mode.
VMax states AC Chargers: Any Quality Brand AGM- Smart & Microprocessor controlled- charger with the recommended specs (not sure what theses are!)
So if WFCO 8735 is not adequate has anyone replaced it with the Progressive Dynamics Inteli-Power 35 Amp Converter/Charger Model #PD4635V?  They claim: 
 BOOST Mode 14.4 Volts – Rapidly brings RV battery up to 90% of full charge.
 NORMAL Mode 13.6 Volts – Safely completes the charge
 STORAGE Mode 13.2 Volts – Maintains charge with minimal gassing or water loss.
 EQUALIZATION Mode 14.4 Volts – Every 21 hours for a period of 15 minutes prevents battery stratification & sulfation – the leading cause of battery failure.
OK, so I am way beyond my liberal arts education so any help and advice would be greatly appreciated!