do pardon me as I can't reply you specifically via pm.
With regards to the deferment, I'm not sure how it goes for your unit/vocation. I was serving my NS as an officer with SPF. I tried deferring via ns.gov.sg and then I called my ns office for further clarification. After which, they asked me to send in the papers to verify that I am starting soon and it will clash with the call up. So I sent in my acceptance letter and showed them the contract.
Just give your unit a call or your ns department a heads up. I'm sure it's across the board, but in the SPF there is a stipulation that states that they can't touch us for 6months once we start a new job.
Worst comes to worst, just give mary a call and she'll probably reschedule you to another training date.
And I guess it also helps that you know the ns department officers and if you're a senior officer and knows the key officers, they can help weigh in your request.
I hope this helps. Somehow. But I guess don't worry, you're already guaranteed a place as CC. So no issues there.