I love the layout and the performance of the WFCO POWER DISTRIBUTION CENTERS.   I am currently using the WFCO 8900 series.
The CONVERTER/CHARGER unit that comes with the POWER DISTRIBUTION CENTER just never worked for me.  I guess I have never really understood the way they are suppose to work.  
I would think they are suppose to monitor the % of charge status and kick into the various smart modes to maintain the batteries to their designed performace mode and capacity.
I replaced my brand new 2009 WFCO WF8945 Converter/charger unit with a Progressive Dynamics PD9260C Converter/charger and it works just like I expected it to - Every time...
I tried everything I could think of to make the WF8945 unit to work out of the box without mods.  I tried large DC cables first....  Then I tried shorter DC CABLES feeding the battery banks (Even tried direct connected 12-inch long cables)...   The WF8945 continued to put out 13.6VDC.  Every now and then you might see 14.4VDC but only for a few seconds then it would jump right back to 13.6VDC output.
I tried to make it go into smart mode at different % charge states.   Even going do to 20% charge state and lower it would not go into into BOOST CHARGE modes for more than a few seconds.   I always thought I must be doing something wrong and not be understanding why they don't work for me since the new trailers still keep coming out with them installed.   I stopped trig to make them work after 2010.   Reading the different forums I see everyone still complaining about them...
As you have stated they seem to be the manufacturer power converter of choice as they different RV trailer models all seem to come out with them installed. 
When the batteries start failing from always coming up dead the guys finally suspect it is the power converter fault and of course go out of their way to replace the unit with a new like WFCO product.  Why not - the trailer originally came with the WFCO unit when bought new so this is what is suppose to be there... Then after a few years the batteries all go dead again the same way as before... Buy new batteries and you are good again for a few more years...  Problem must be the batteries - right!
Only the guys that know what to look for survive with them I suspect...
After giving the situation a good college try in the early days I finally just gave up on them....   
Since I changed to the PD9260C converter/charger unit my original standard issue GP24 12VDC Interstate batteries installed in 2008 are still performing.   I am not the easiest guy on batteries doing my off-road style of camping.  I cycle my batteries from 50% to 90% charge state every day on my trips.   I am just now starting to see a slight drop off in battery performance after 6 years of use.. 
This gives me more time to worry about other important things like trying to figure out why my propane sensor monitors keeps going off in the middle of the night even when we have the propane tanks shut off at the main valve...  This is probably due to my 50% charge state depleted batteries or perhaps from all the good beans we like to eat every day...