In some situations you might need to combine the data from two monitors in your simulation; for example, if you want to calculate the power absorbed in a structure you might want to subtract the transmitted power in two power monitors. Naturally, you want to make sure that the settings for the monitors are consistent, especially that the frequency points for both monitors are the same. For this situations it is a good idea to use the global monitor settings:
Also make sure the monitors have the option “override global monitor settings” unchecked. This simple procedure can save you some headaches when post-processing the data from the monitors!