I don't fully understand why the 10.6 update does it even after reading your link IRRenewal
Would I be correct in saying that previously the FMC would allow a level segment in the descent path, but now it will only allow a continuous idle thrust descent, which is why it gives me speeds of 210 kts with 95 track miles from touchdown? It is trying to extend the glide range by using a low speed? I notice that whenever you select direct say the FAF it reduces to the flaps up speed even if you are 100 miles away.
Its really put me off VNAV. You spend so much time programming it, its just not worth it especially on short flights, I just can't be bothered now.