PC?
RSM is a higher appointment than PC leh.
For example, if the CO doesn't want to have the GP Car for personal
use, the next person entitled to it is the RSM, not the PC, OC,
2IC.
Within officers, even if you 2 are the same rank, but one holds an
appointment like, S3, the one who isn't S3 will call the S3,
Sir.
But in the end, so what if you salute ppl, IF you don't respect him
at all? Its all actually respecting the person.