Full official specs: http://www.olympus-europa.com/site/en/c/cameras/om_d_system_cameras/om_d/e_m1/e_m1_specifications.html
At first I thought, fine, they just don't wanna add more programming cost to creating menu options with e.g a high bit rate mode.
But looking at video specs it seems to already be two modes for 1080p, one "high" bitrate 24 Mbps and one lower 16Mbps..
So it's just tweaking of numbers, this was a deliberate choice, what is going on here?!