Of course they behave differently. The XY graph is passed a value to apply to the x axis. A waveform graph gets start point and increment and the default for these are 0 and 1. With a waveform graph, if all you did was set min and max, that wasn't correct. I can't look at your program to see what you actually did since I only have 7.1. As I mentioned above, you can set the offset and multiplier. So, if from your instrument you can get the starting wavelength and the wavelength increment between each data point, then these are the offset and multiplier settings and your x scale should look like the instrument does.
