First two videos of ADL I found: Splits at 20 seconds, splits at 2:37 seconds, both from lv 90 cap. http://www.youtube.com/watch?v=2oOVyy7eeTQ for the long no-split against pearl and homam and other terribly geared DDs. Split > almost everyone instantly dies at least.

The split occurs sometime under 60% becoming more likely as its hp goes down, and there probably a certain amount of time that has to pass before it can split again.