Super sweet ride. I am working on same size 615 from a couple of years later, and sadly too small to be a keeper.
But looking at where the engraving appears in these pics, you may want to check that your granny ring is set the right orientation on the spider. I found out that there's a wild (and not useful) bouncing effect when the biopace rings are rotated away from their ideal, and it's very noticeable with the granny!
ps. mine also has hubs that say "Sansin Sealed" but they are very much loose-ball type bearings.