It shouldn't be a problem. In your scenario, Sing Immigration takes note of when was your first arrival in Singapore and what period of stay you were allowed. It would seem to me that you should be ok to return within two weeks; if you're American you would be allowed (if memory serves) 30 days upon entry. Thus if you exited Singapore but returned for a second time within the original 30 time frame you should be ok. Singapore knows it's a transit airport and quite a few business travelers mirror the in and out and in again routing you're concerned about. In a worse case situation show the Immigration officer your return ticket if asked. I really doubt you're going to have any problems.