Man, you are definitely on to something here BFL. I now understand why the SOC on my Victron is higher than what I think it should be wrt to the total amps drawn. It's the Peukert setting in the meter. Sure it doesn't account for temperature but plugging numbers into the spreadsheet is showing me that my batts have WAY more actual Ah's than what I've been thinking. Which explains some "behaviors" I've been seeing after boondocking like the converter tapering amps sooner than I would expect (because it's closer to full than I'm thinking it is). I think a SG reading after the next trip is in order. I need to confirm some of my suspicions.
EDIT: BTW, the Peukert exponent for your T1275's is 1.19.