It seems like there's something missing. I can't figure out how the rows are spaced relative to each other.
The pitch is 1.257mm. The distance between the centers of 17 of them is 20.112 -- that doesn't really add information. What about the 22.578? It seems to be measured from some arbitrary point within the pad to the same point on the opposing pad. The B diagram doesn't show what that point is. It looks like it might align with the right side of the smaller pad in A. If so, that would mean the pad in B could be considered split into a rectangle of length 1.5 (with the rounded 0.4 bit tacked on the end), and the distance between the rectangles (ignoring the rounded part) is 22.578. That spaces opposing rows, and adjacent rows are placed by centering. But this doesn't seem to fit on a grid -- 22.578/1.257 = madness.
Am I missing anything here? (And why would someone design something like this?)
The module itself looks like this: