This was all about having more fuel AT THE OTHER END, not about having too much weight at take off.
I find it hard to believe that a B737 would still be overweight for landing after a five hour flight to Bali unless it was tankering fuel and if it was then it would be possible to increase the flight burn by 170kgs on the load sheet to bring the a/c back within landing weight.
Possibly much more to this event than is obvious?