Looking at the various charts I would say that Eog does indeed have a 0 CP multiplier. The cost compared to the similar Elven steel seems to indicate that. Eog is almost 1/3 again as expensive as Elven steel with very similar bonuses and worse maneuverability. So I think the 0 is intentional.
Now that is for the properly alloyed Eog. The white and black pure stuff actually causes a penalty per piece worn. This may work well for anti-magic manacles, shackles, and gags. Causing casting penalties even beyond the normal for these items. But the astounding cost of these would make them only useful for the most extreme circumstances.
I suspect the Laen full plate CP may be a typo however we will probably have to wait for Thom or Nicholas to give us the official answer.
I hope this helps,
-Pyrotech