Re: hips and shoulders
In answer to the o/p I find yes and no.
Yes in as much as if wanting to use your shoulder then the connection with the hips is imperative.
Secondly I would say that two things can be practiced:
1) Turning from centre.
2) Turning from hips (koshi) (kua)
I would ask you Mary as to which part of the hips do you feel you are moving ie: the whole bowl so to speak or do you concentrate on relaxing the back of the hips and thus that pivotal point.?
Personally now I find the shoulders 'disappearing' when turning the hips, going 'passive' rather than 'active' and if I am reading your exercise correctly it would then lead me more to a kokyu ho type exercise.