Of course it descends earlier! For a
given IAS a light-weighing aircraft will fall out of the sky. Reverse for heavier wieghts.
Compare now to a case of a
given AoA for descent. The clue is in the green dot speed which varys with GW ( or in nonglass-speak "best lift/drag speed clean" ).
Muse over those 2 lines above while dusting off your Student Pilot theory book and the penny'll drop (without a FMC box!)
