Yeah ... I managed to get hold of a copy of "RAAF Flying Boats at War" by Joe Leach.
From it, there would seem to be three Catalinas lost in landing or taking off at Balikpapan.
Chapter 17 - "The Invasion of Balikpapan" he refers to
"...another 113 ASR aircraft, A24-101, together with a borrowed American Catalina, arrived with medical supplies and blood..."
(this follows his account of General Morshead and the a/c in which he was transported being lost after "being put down")
... "The RAAF liasion officer on the command ship, with concern for aircrew, advised the staff officers that in the prevailing sea conditions, the aircrafy could not be guaranteed to put down safely. Asked if there was a reasonable chance of landing and the medical supplies salvaged and got to the beach, the reply was 'yes, but very risky' Without hesitation the General said 'very well, tell them to go in' Both landed sucessfully, but after unloading, broke up while attempting to take off."