I just realized about the three axes, not just two and the use of the FEX submission -- I don't have it and don't want to mess with downloading, but to illustrate how to get the two values at the same scale on the proper axis with the first two using builtin MATLAB abilities --
pos=[0 40 75 80 120 145];
The above yields
where both red curves are on the RH axes and scaled per its scale. This happened because both were drawn while that axis was the current axis of focus.
I don't know precisely the interface for the addaxis function, but it will do the same -- subsequent plot commands will plot into gca by default so if you plot the observed data in sequence and then try to add the fits, you'll be changing focus and thereby creating the issues you're having.
The fix is one of two possibilities:
- Add all data to each axis in turn as it is created and remains current as shown above, or
- Save and use the axis handle as the target axis for the subsequent plot commands so they're added to the intended axis.
Either of those will, as suggested before, solve your problem.