It's a pity that the only airlines that can issue a return BP is SQ if you fly to CGK on SQ both ways, as far as I know.
I don't think the Transit Desk at CGK has the capability of issuing BPs, because I did not see any computer behind the counter though (or may be I am wrong).
Recently I did another turn-around at CGK on SQ. Slight hassle, because the transit agent was told that for Indonesian passport holder, the passport needs to be checked by the immigration first. After waited a while, I was allowed to go upstrair by escalator heading straight to the lounge. For me, I would say so far 50-50 chance for smooth transfer at CGK.