Sorry Mate, but that's CBM not CBMP. You can step outside parter in Tango without any swing.

Dear Phil.
Reviewing this post and tried what you said today. you pointed out the problem may occur in CBM.
In 5 steps of Tango, I got hang of it on 2-3 to wait for his body weight change, the problem resulted from (1)stopping use of standing leg and past my right foot without relation to left foot ( bad habit),
(my left knee should be roll continuously forward until I almost kneel then releas my right foot together with right side leg top (leaving the right hip behind) passing left foot ) or(2) my poist and head do not work outward enough with compact contact with my coach (sometimes I omitted it.) 3. I am not sure if I misunderstood, I am active in 5 step. if my standing foot work well, I have right timing , my coach will not strain his ankle due to my fault.
I am interesting in "softening" which I am not always keep it in my mind . Try reverse turn as you prescribed how an advance dancer do, I feel better. I call it : preplaning.
" CBM is inevitable if the turning action is to be continuous throughout the trun." I still can't catch it. maybe later I will. Thanks.

I noted that the CBM in a series of basic foxtrot ,V waltz ... body rotation slightly advances to the moving leg is very common. Is my understanding correct?

In foxtrot, waltz, etc, yes the body rotation known as CBM is slightly in advance of the moving leg, in effect, the body "leads" the leg and thus places the moving foot along the path the weight is taking, which is to say the moving foot lands at least partially overlapping the track of the standing one.

Or perhaps we should say the standing leg sends the body, and the body leads the moving leg?

Some who teach this CBM for the W,T,Q prefer to teach the Viennese Waltz differently , with the leg and body turning together. This seems to be supported in the way VW figures commence from an underturned alignment of not only the body, but underturned feet as well.

I like the tought about standing leg sends the body--> body leads the moving leg along the path way where the weight is taking, detail technique described by key words.
Last night , my coach told me to hold RF ahead the LF in CBMP while my body weight travels onto left heel on 1 ( natural turn, waltz ). There is a delayed RF swing and very strong CBM, head is extremely left side. I am not sure whether it is better than the old one.

Yichin. Dead right . Both feet on the same track. Shoulders still, stepping across the body. Try to do a Contra Check without CBMP and your in trouble.