Interesting. Let's say you are right and Singh means "salary" (It's not clear). Here's something from Wikipedia about that:
By the time of the Hebrew Book of Ezra (550 to 450 BCE), salt from a person was synonymous with drawing sustenance, taking pay, or being in that person's service. At that time, salt production was strictly controlled by the monarchy or ruling elite. Depending on the translation of Ezra 4:14, the servants of King Artaxerxes I of Persia explain their loyalty variously as "because we are salted with the salt of the palace" or "because we have maintenance from the king" or "because we are responsible to the king".