You would think so, if you didn't know... it looks like both cabs are correctly matched.
But it's one of the few that isn't, because what roughly happens is that *both* cabs try to draw the full power (because each is correctly matched to its OT tap), with the result that the output tubes try to produce up to double the power (bad for them) and the 8-ohm section of the OT winding - which carries the current for *both*, because it's part of the 16-ohm winding, not separate - is overloaded.
There are two ways of running an 8 and a 16 ohm cab together - either as Mesa says, 16 from 8 and 8 from 4, or you can simply run them in parallel and treat them as a 4-ohm load (it's really 5.33 ohms, but close enough) and connect both to the 4-ohm jacks. I think this sounds a bit better, but 2/3 of the power goes to the 8-ohm cab... which may or may not be a good thing, depending on the cabs.