Do you mean that a volume of ONLY 6 was loud enough to cover the rattle? Then, it must have been a small rattle, indeed... So, why didn't you think of doing so in the first place? It would have saved you lots of time, aggravation, not to mention the large bill...
No - the rattle was gone (repaired) before I turned the stereo on. For two reasons - I was getting slightly pissed (literally) waiting and I wanted to drive my car over some significant bumps to make sure (the rattle was gone). Also to calm the Daihatsu employee's nerves down, with me at the wheel.

All up, I paid a total of Rp 41,000 for both "repairs". (They didn't charge me for the real one, which, it turned out, was something to do with the front brakes - maybe a brake shim, or something.)

My bill at the bar, on the other hand, was in excess of Rp 100,000, but I had sort of a good time. I did try (jokingly) to get Daihatsu to pay it. Everybody laughed, of course (including me).