In Rome, magistrates (and later the emperors too) each had a fixed number of lictors, according to the rank of the office they held. Is a similar regulation of the number of retainers according to rank known for the Achaemenid Empire? Or other ancient Eastern states?
In general, this type of thing is not well documented for Archaemenid history. Also, in Persian administration there was a great deal of autonomy and variation across satrapies, so what would be true for one, might be different in another. Speaking of royal judges, which were similar to Roman magistrates, for example:
You can read the rest of the paper for more information, but the upshot is that it would be difficult to make any conclusive statements about numerical policies for such things.