We now have a discrepancy between what Rigol says (according to Batronix), and what is actually printed in the Manual. So, I'd like to see whether the official firmware has 14 or 16 bits for arb. wave forms. If you could produce an arb. form with, say, values 0x4000, 0x4001, 0x4002, 0x4003, and 0x4004, and check with a scope whether there are five different voltage levels or just two. I think that should close the case.
Screenshot would be nice!