I've just received another Integral today via UPS, and looking at the yellow / purple lines on each side, I'm having difficulty believing that it's intended to represent the thrust line, because on one side the line bows up, and on the other side the line bows down. In both cases neither is a straight line, so you can't use either one to determine an appropriate straight line.

Does anyone else have the same problem, or am I the only one?