In the past I have run into the HKG visa office morrons as well. And although I am not on a student visa and do not work as an English teacher, my experiences in the Lippo Centre were nothing to be writing home about in a pleasant way.
Although dressed in a suit (I was in HKG for business), having brought all the documents, and staying polite, I was hassled and asked irrelevant questions. I ended up being given a 30-day without extension; the same I could have gotten simply upon arrival at CKS airport in 10 minutes flat.
Fore the last number of visa-renewals I have used the Taiwan's Singapore visa office....let me tell you, it's a world of difference.
Package deals/flights to SIN are about the same price as to HKG,a nd it's a nice change of scenery with better shopping than in HKG as well. Stay in one of the Hotel 81's and pay < 1,000 NT a night for a clean room. If you want to stay at the Hilton on Orchard Rd. for about 170 S$ p/n (NT 3,200), please let me know, and I'll help you with the booking under our corporate rate...