Even before Asuki went in it never had you 400/500 ft high.
It has always been just a wee bit high, in my mind about 50ft ( I haven't calculated it like the above posters but that's what it seems like when I fly it. The problem is one of energy management more than profile management. If you are at Sheed and still trying to slow the aircraft then you have probably carried too much energy into it. If you are going to have a tailwind then you want to be fully configured by Sheed, if no tailwind you can take final flap after Sheed.
Use of automatics also plays a role in cocking this approach up. If you mis manage the altitude selections and the machine begins to level at 2500ft you need to abandon the automatics quick smart and fly the aeroplane because the automatics will be too slow to re establish an appropriate rate of descent. The VSI can't be allowed to reduce if you want a nice stable approach. Whether that is achieved soley by looking out the window or if the VSI is kept in your scan is neither here nor there.
hmmm....
I think both of you need to have another look at the descent gradient in ft/nm.
I don't need to have another look at the gradient Lead Zepplin, every time I arrive at Sheed on profile I just look out the window at the threshold and glance inside at the airspeed every few seconds and it all seems to work out fine.
Having said that, if I was tired and had had a long day and there was a tailwind I may well request the RNP, no big deal.