I would be interested in seeing an image of the bowl with an angle much more similar to those on the site I referenced. NW662 does seem more similar to me, but a different angle would let me see rib structure better, as lighting and angle could be causing the ribs to looks slightly different. An image at the same or close angle would be great. It would also allow us to see the curve of the sides better.
The ebay piece, at least to me, seems to have the ribs stop quite short of the rim, where this piece appears to have them fade, but not stop..... Personally, although similar, I do not think these are the same piece.....
The difference in appearance of the ribs could also be a byproduct of the color difference between the subject bowl and the example on the site.
Craig