I think I've read that Famitsu had a better coverage than Media-Create too.
That is, you can't trust one more than the other. Each one of these trackers are forced to a certain extent to approximate the uncovered retailers (through differents mathematical algorithms). That's where the errors come from. Sometimes, Famitsu will estimate this part better than Media-Create, and sometimes it will be the opposite, you can't really say.
So you have to relativise the numbers that you read. If Famitsu says Game X has sold 12,500 units and Media-Create says 13,644 units, you must think : Game X has sold approximatively between 12,000 and 14,000 units, and make your personnal analysis based on this bracket.
This, is true for the NPD, GFK, VGChartz and Chart-Track too. Don't think their numbers are exact.
I don't know if that helps you.
