Indeed. If I can recall correctly, Anker's estimates are usually based on 80% volume, and given that the BassUp function is on by default, I would assume that it was also on in there testing.
I know there have been reports of the speaker lasting well less than advertised. If this is the case with your unit, feel free to shoot an email to email@example.com and they will gladly issue a refund or hook you up with a different speaker (whether that be another Boost or something else entirely). Either way, they'll make sure you're getting the same value (perhaps partial refund, too).