Dialing in Midnight Kid

Socratic Monologue

I recently replaced two Morningstar PWM controllers with a Midnight The Kid.  System is 12v 440ah (4 6v golf cart batteries), 4 x 130w 12v panels.  Panels have been rewired for 24v for the new CC.

I think I'm going to have some ongoing questions as I get the new controller dialed in, but my current one is this: the Kid reads voltage about 0.3 - 0.4 v lower than the Trimetric when charging; at rest the two agree exactly.  This is causing the CC to absorb at about 14.0v at the batteries; they're not getting fully charged (as judged by the complete lack of bubbling, and the Trimetric reading very much below 100% when the CC goes to float; in the past the Trimetric would often read over 100% before it reached the 'charged' volts/amps criteria).

I understand that the Kid might be more accurate with a WBJR.  Is adding one the only good solution, or might it be acceptable to simply increase the absorb voltage setting on the CC so the voltage on the Trimetric (which has always agreed with a multimeter at the batteries) is the appropriate absorb voltage? I don't want to adjust the voltage offset, since the CC agrees with everything else while at rest.

I don't quite understand how the temp compensation settings work in the CC, so I haven't changed them from stock.  The CC and batteries in are in the 30s F currently (they are in a detached unheated garage, which doesn't go down below about 25F ever).  Could this be (part of) my problem, and if so how should I set the TC?