Keep your options open as long as possible.
If you can get double the salary by going back now you should go.
The situation in the US may change again and if you wait a year the opportunities may not be as good.
However the one year of management experience in Singapore may dress up your resume a bit and get you a better offer in a year.
OTOH - If you are that good that they want to keep you here, maybe getting an early start in the US and picking up the promotion there is the right move.
Me personally - I would be sending my resume's out in the US to see the interest level. I would start negotiations for the manager job here and if the contract is at will (meaning you can leave anytime) you can always tell them you got a better deal.
As a manager it's frustrating to me when an employee wants to play this game. However I never begrudge them the opportunity.
i.e John comes in a tells me he's got an offer $10k better than he gets now. I meet the offer. He comes back and says they other guy met that and added $5k.
Good for John, I say. Eventually I run out of money and John decides to stay or go.
To me it's just business.
Use your negotiating power while you have it but make sure you really have another place to land.
