They've got the budget and manpower to maintain them Rock. They're oil rich and don't have a soaring debt like most of the Asian nations. They bowed out of the "recovery" packages offered after '98 and they have been all the better for it. There is a very credible danger that they may have to square off against the Indonesians and they view China as a threat to their interests. I wouldn't be surprised to see further purchases but as they are a frugal nation I wouldn't be looking for them to buy the next round until they have the cash in hand for them.
"The purpose of fighting is to win. There is no possible victory in defense. The sword is more important than the shield and skill is more important than either. The final weapon is the brain. All else is supplemental." - John Steinbeck