It depends on how much muscle mass you have, which it should at least approximate properly unless you did not enter the bodyfat percentage correctly. I think this just uses an average base metabolic rate as well, so if you fall significantly outside of that norm (much slower than expected, for example) then that will skew the results towards the wrong end of the scale also.
I could only replicate that by setting the activity level to 'very active' (hard exercise 6-7 days per week). At 'lightly active' it recommends closer to 2400. Seems reasonable.