Similar, but different...the unwinnable argument...although, I'm sort of leaning in your direction this time...See, Putt4Par, that's why I don't answer stuff anymore. I end up arguing with two-bit bagchuckers who failed as a moderator about what's deep and what's not so deep. Not worth it, man, just not worth it, even for someone who makes as little as I do.
This parlor talker would guess that the -300 procedure calls for a good prompt descent to more breathable air, but not in such a way to cause undue stress on the aircraft whereas the NG calls for a good prompt descent to more breathable air, but not in such a way to cause undue stress on the aircraft.