Actually, there's no need to confuse him further. NS is NS, aka
consciption or active-duty. Reservist is reservist, but in our
context called NSmen cuz they're ops-ready & not reserve-duty.
Reservist is not "part time NS."
If the TS is asking about reservist pay, well, the SAF has a system
called MUP (make-up pay) claims. All one has to do is file for
compensation of his lost wages (monthly pay divided by number of
days called back). Fraudulent claims are chargeable & always
checkable (eg. CPF & income-tax records). If you're studying or
unemployed & didn't file a MUP, then the SAF will pay you only
the equivalent service pay.