I'm not a judge, but my DD is. Simply, it's not all about the jumps OR the number of falls. It is a compilation of all of the elements: spins, footwork, presentation, skating skills and speed, execution of elements. If Skater A falls on 3 jumps, but, has excellent spins, great footwork, and, the jumps that were executed (whether falls or not) - are executed very well with speed, ice coverage, checkout, Skater A will be placed over Skater B who went clean but skated cautiously, had weaker spins, weaker elements, etc.
Also, one skater is the reference skater - the first one. All following are ranked above or below that reference skater ... it can be an art form to do.
This is why I don't like OBO. It's too hard for skaters to be able to understand their placements.