House Battery and Surefire Battery Separator Issues

[Besags]

I have a 2007 Sportsmobile E-350 with a 6.0 L diesel engine. I bought it about 3 years ago and it came with a 4D lead acid house battery, Surefire 1315-200 battery separator, one solar panel and a Blue Sky Solar Boost 2000E controller. My frustration has been trying to determine the condition and voltage of my house battery. My understanding was that the front cigarette lighter socket should indicate starting battery voltage, while the solar controller and cigarette lighter sockets in the rear should display house battery voltage. Normally though all the readouts are the same and they only changed when the Surefire battery separator connected. The voltages would then go up a little but still read all the same and then when the separator disconnected drop down to the original voltage. At first I just assumed that all the batteries were good and the charging system was doing it’s job,, but it did bug me that they were all the same. Yesterday I finally dropped the house battery to check the electrolyte level and voltage. To my surprise the house battery voltage was 10.5 volts, but all the other readings in the van were 12.7 volts. So i started checking the wiring to try and figure out how the system works and what was going on. I traced the two positive feeds to the separator, house battery and start battery. The house positive cable is attached to the left post of the separator and the start batteries positive cable is attached to the right post of the separator, looking at the separator from the rear.. Also attached to the right post is a smaller gauge, #6 or #8, wire that runs forward and to a very small circuit breaker that supplies power to my DC fuses for the house system. There is another wire at the circuit breaker that goes back to the rear of the van and supplies power to the Starfire a/c relays. I concluded that my van’s DC system has been totally powered by the dual starting batteries, so I switched the wire from the start batteries side of the separator to the house side. Now when I check inside the van I get 12.7 volts on the forward cigarette lighter sockets and 10.5 volts on the solar controller readout and the aft cigarette lighter outlets. I think the system is now set up correctly, although i would like some feed back on this to make sure this is correct. I don’t know if the van came wired from the factory this way or maybe someone replaced the separator and wired it incorrectly., but it does appear from the way the wire was routed and it’s length that it came this way from the factory.