I will be flying into the Singapore airport a little after midnight in the next few weeks after a very long flight and leaving again before 9am. I'd like to get some good rest and a nice shower in the AM without clearing security. Based on some of the old threads, the Ambassador Transit Hotel in T3 seems to be what's most often recommended. I checked their website and it says the rates are based on a 6 hour block. What does this mean? I can only stay there for 6 hours unless I want to be charged twice the quoted rate? Anyone with recent experience can explain this to me? I'm a budget traveler without any airline lounge privilege. I don't mind forking over a reasonable amount of money to get some decent rest though. Also, will I need to pay the hotel in SGD or can I use my American credit cards?

Thank you in advance for any suggestion.