Hi, as someone who works there, I can tell you the salary range for fresh grad is quite correct. Where u fall within that range depends on your honours and past work/internship experience. If you are male and completed NS, your starting pay is higher to compensate for the two years of non-employment, as with most civil service jobs.

IO is a degree level job, and it is not easy - depending on where you go. 'Officer' is a general term. You are a government official upon employment, hence the title.