If the ethicist's utility function is broad enough in scope to subsume (or at least recognize) that what is good for the economist is ultimately good for the rest of the system (if that were the case), then there might not necessarily be a need for distinction of utility functions.
It is possible the economist's utility function might hold some underlying (and unintentional) positive ethical effect.
I think the last block of text is key.
If the ethicist's utility function is broad enough in scope to subsume (or at least recognize) that what is good for the economist is ultimately good for the rest of the system (if that were the case), then there might not necessarily be a need for distinction of utility functions.
It is possible the economist's utility function might hold some underlying (and unintentional) positive ethical effect.