Yellow Dot Conundrum

You mightn't have noticed, but colour laser printers have been encoding data on the paper that you print. Apparently this is because of a US thing against money forgery - there is more on the EFF about decoding DocuColour encoding and also some information on Seeing Yellow. But don't believe me? Well ... look at this innocent looking certificate I got from the university:

Focusing onto the area outlined by the dotted outline - you can see this:

It's very feint and hardly noticeable - it's easier if you tilt your head a bit especially on an LCD monitor. But using some Photoshop-ery with the Black and White filter - the data is revealed:

From this, it can be seen that the dot grid repeats itself - there's a top row and bottom row of data.

That crop wasn't such a great one since it straddles two different rows of data - so I cropped again, this time, focussing only on the top grid row of data. By isolating only one grid square - we see this:

I can tell the column G represents the parity column - it's obvious from the image above, but everything else so far is a mystery. It doesn't conform to the coding standard that the guys at the EFF have described. It seems to consist of 14 words of 16 bits each with one parity bit. More puzzling is that there's something which appears to be different - the row below this row - however, I haven't looked at that yet.