I am not sure where exactly the monitor is located. As mentioned previously, moniotors give total fields. If you think it is ok, you can use the example file to get the result and save it to matlab data file, and then import it. Do you have difficulty in using the script file?
If the monitor is on a waveguide and you think this waveguide mode is the result you want, you can use an mode expansion monitor to get its mode profile, and the S parameter or a or b coefficient, and modify the mode amplitude.
If the matlab version is not supported, then there is nothing we can do right now to use it. But you may try zbf data format.
If the mode profile is what you want with a correction of the amplitude, you can directly use a mode source for second simulation, and use transmission data to get normalized result. As you know, T=transmitted_power/source_power; each simulation has its own source power.eg
So you can do like this:
I hope this helps.