Something I've never understood about VGC's sales numbers on the front page

[IseeLight]

Jay520 said:

The gap has been shrinking, just slowly. PS3 only outsold X360 by about 20k a week lately, so there wouldn't be much of a drastic change.

Gap at the beginning of the year: 4.1m
Current gap: 3.3m.

Do they just update the graph less then since I see the gap as 3.4 not 3.3 on the graph.