Hi Scott,
I was looking at the magnetic forces/deflections we measured today on the BL13 ID and I realized that the BL13 ID phases 0, + 1 and -1 are all Vertical polarization.
The phases to be measured for this ID are 
NOT -1, -0.175, 0, +0.175, +1
but -0.5 HP-, -0.175 CP-, 0 VP, +0.175 CP+, +0.5 HP+
Hendrik confirmed this.