When you look at the "Update history" at
http://kakaostats.com/tp.php?t=91739and choose the WU's view on the table below the chart graph, you can see:
2008-01-30 22 WU's at 14:00
2008-01-30 12 WU's at 17:00
It should rather be equal to 2 and 1 WU's respectively.
Could you check wheather it is an error in formula or in error-ed data imported into stats?