Sorry to be going on about this, but it's more for my own clarity. I just found this:

http://www.avid.com/nab2005/storageCompressionChart.pdf

Clearly the Meridien resolutions are indicatied as having a fixed duration per GB of storage space

Gerrit

There's one important word on those tables that you seem to be ignoring - Average. All those figures are average, sometimes it may be higher, sometimes it may be lower, depending on the material. MJPEG compression will presumably be more affected by image complexity rather than movement.
Please try it, digitise some black, or some colour bars, then some programme.  For all the compressed resolutions you will get different file sizes.

regards

Brian