Boeing revises ranges of their aircraft

I already wrote back in 2012 that there is something not adding up in Boeing's range esimations for the B737MAX. Now Boeing officially revised the range numbers for all Boeing aircraft.
Boeing says this has to do with revised assumptions for pax, bags and seat weights. We don't know how Boeing revised those numbers, but as I wrote back then something did not add up from the beginning when comparing the range of the B737NG with the B737MAX.