So for example air force technicians, the regulars will be under
MDES,but the NSFs will be using military ranks?
yes. My friend is an airforce technician (regular), his boys
called him, Sir, or Mr Tan or Jeremy. He called his boys, CPL or
their name, But he is equivalent to SGT previously.
He also called his boss, Sir, Mr X, or his name, although he is
a warrant previously.
In another words, the addressing is totally messed up
now.
I think another friend of mine also convert to the MDES rank, he
is a mechanical engineer instead of the PC(officer) in SAF
now.
Expert as is in expertise, meaning some1 who
is specialist in this field of work.