Regarding DAS's early float, is it not possible, just as BFL pointed out earlier, that voltage drop could be causing the controller to be "seeing" a higher Vbatt, and going into float prematurely?
Or it could simply be how the controller is programmed. Many chargers are factory preset to go into float too early, it seems.
Page 46 of 56 of the manual says float is at 13.8v default, and has an upper and lower limit. Does this mean the controller is adjustable? If so, DAS could set float at the upper limit of 14.2v to extend abs charging ( a little low, but way better than 13.2v).
Manual