The heavier aircraft ,due to weight has higher kinetic energy,gets to descent speed(best l/D ratio)early.Light a/craft stuffs the nose down to reach it's L/D speed,once there meanders down some time later.Both reach the same spot(about 75 miles from FL350).
Used to talk of this Circa DC8 in the 70's..
Cheers...needless to say been done in the Sim'
