You might want to consider paying the relatively small amount extra to book business class: Garuda have a habit of overbooking economy and bumping people off so that hi-sos can get on. Would never happen to a business class passenger but I know plenty of people it happened to in economy. Also, DPS is a hole of an airport and very few places for people to wait in comfort (which could be a while!), but at least the lounge is adequate.