God I love seeing those viscosities of SSO after 15k miles. I think always in grade when sampled right. I'd like to see more TANs on these samples....if TBN should always be higher than TAN, I imagine at a TBN of 2.0 you might start seeing unpleasant TAN's....
That being said, look at that wear! You could've shown this UOA after 5000 miles and people would be saying "looks good", besides the low TBN.
Really nice slug of calcium there too.