Curve Offset

Does anyone understand what is controlling the curve offset. In one instance (image offset01.jpg) it does precisely what I'd like it to do, offset the vertical curves perpendicular to the curve they are arrayed along. For some reason this is the only location that I've found so far in the model that without any work does what I'd like it to do. The other cases give me what I would expect, offsetting the curves based off a global XY plane (image offset02.jpg). Now I'm pretty sure I can figure out how to get it to offset the line correctly but I'll need to jump through a bunch more hoops and this file is already huge. I'm just wondering if I'm missing something in why it is working for me in one case but not another without changing anything.