The probe was rotated for the Y= -8 and -9 cm measurements so Bx and Bz are mixed and need to be rotated back.  The following formulas do the rotation:
Bx = Bx_rotated*cosd(45) + Bz_rotated*sind(45)
 Bz = Bx_rotated*sind(45) - Bz_rotated*cosd(45)