In May Mr. Megatop and I are flying to Bali from Bangkok via SIN on SQ, so I figure we can change money at the exchange desks at Changi. They seemed to have decent rates, particularly for an airport (no doubt the S'pore gov't requires competitive rates on par with city offices). Ideally, the Amex desk (I'm a cardmember x2) will offer the if-you-don't-use-it-you-can-change-back-at-the-same-rate program because we'll be coming back to Singapore after Bali.

If someone knows for a fact that I can't change into Indonesia Rupiah at Changi, please let me know so I can make other plans.

And if someone knows which exchange desks do and don't offer the same-rate-change-back program, I'd very much appreciate knowing that too. I've seen it at several places, but haven't tried it in Singapore.