I just had a flight at SIN to HND at 6:20 AM connecting to CTS at 8:00 AM. So 1 hour 40 minutes connection time, 10 minutes shorter than yours.

Unfortunately the flight was delayed, so as far as I can tell from discussions at the transfer desk, many people missed their connecting flights. But even without the delay, it was a very tight connection.

Flight was 24 minutes delayed and arrived at 6:44 AM. By the time I cleared immigration, customs, picked up bags and arrived at the transfer desk it was already 7:36 AM. Too late to do anything for the original 8:00 AM connection.

Queue at transfer desk was not long but staff were very slow and took almost 15 minutes per guest to settle their problems. By the time it was my turn it was 8:00 AM and too late for the international desk to domestic transfer even on the new rebooked flight at 9:00 AM.

But NH staff told me was still possible to check in at the domestic counter side (30 minutes before flight time). I don’t know why staff asked me to queue at the transfer desk when they couldn’t do anything anyway. Would have been better if they had just advised people to go straight to the domestic side.

But note that at the domestic airport if you have odd size baggage, you can only use the manual check in counters, so even more queueing.

My tips - plan for delays. Instead of wasting time at the transfer desk, I wish I went straight to the domestic counter to check in there - more staff there and queues were moving faster there.

At immigration, maybe try to join the non-QR code line. It was much shorter but I got herded into the QR code line. But bags came out same time as immigration ended, so even if you saved time on immigration side you might still be waiting for bags.