Q: See the attached image and notice that Infilled Plates 470 and 471 do have same orientation but different local axes.
A: The vector pointing from I to J defined to be local x- axis. The cross-product of vectors IJ and JL defines a vector parallel to the local z-axis, i.e., z = IJ x JL The cross-product of vectors z and x defines a vector parallel to the local y- axis, i.e., y = z x x. The origin of the axes is at the center (average) of the four joint locations (three joint locations for a triangle).Please look at the model and you will see the logic is as stated. For your square plates, the local X axis is parallel to the line defined from Node A to Node B.