Some RTUs have the ability to handle multiple meter runs. Profile, will by default, attempt to map the meter runs in the RTU to the meter runs used in Profile using a straight forward mapping, e.g. meter run 1 in the RTU = meter run 1 in Profile, etc. If your configuration is more complicated than this you will need to manually allocate.
See the ‘Adding an RTU‘ section for more details on how to add an RTU.