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:
The royal judges are attested here for Seleucid Babylonia, in the particular context as recipients of perquisites from the king's sacrifices at the New Year Festival at Babylon. The royal judges were a Babylonian institution, attested from Neo-Babylonian and Achaemenid times, with judicial authority to decide important cases. Although nothing specific is known of their selection, composition, or function in the Seleucid period, knowledge of their existence adds another Babylonian institution, continued under the Seleucids, to the general body of material from which the impact of Seleucid rule in Babylonia can eventually be assessed.
Babylonian Chronicle Fragments as a Source for Seleucid History. S. M. Sherwin-White, Journal of Near Eastern Studies. Vol. 42, No. 4 (Oct., 1983), pp. 265-270.
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.