Thanks all. I guess CGK doesn't have the common airside for departing and arriiving pax as, say, KUL and AMS.

Looking at doing a KUL-CGK-KUL (will be in KUL anyway) for the 30 XP for less than buying them (€10/XP) for environmental offsets + get miles and huisjes to boot. KL SIN-DPS runs about 2.5x as much for the same XP (and only slightly more miles) and looks like KQ BKK-CAN runs about the same (though flex on the latter and lite on the former). Has to be on ST airlines and there are not many 5th freedoms around Asia.

Did a KL BKK-TPE-BKK turnaround a few years ago and that was easy. Just wasn't sure about CGK.