Have you checked using your friends meter? Some are just more accurate than others even those made by the same manufacture. Also he probably does not have the exact same trailer with the same options.. AND are you sure you have not left an outside light on? or one in the storage bay?
2004 Chev Silverado Duramax optioned past the max. 2009 Jayco Eagle 308 RLS 765 watts of solar, 6-6 volt batteries (696 amp hour), 2000 watt (4000 surge) whole house inverter.
140 days boondocking in 2016
211/2015, 196/14, 247/13, 193/12