If that is true, and I do believe what you say, I definitely have NOT been doing the procedure correctly.Where is this published? It makes me wonder what else I am missing.

Thank you!
Hi, to answer your question, please see following, especially part 'b', copied from Mavic manual:
Precision Landing
The Mavic Pro automatically scans and attempts to match the terrain features underneath during Return to Home. When current terrain matches home point terrain, the Mavic will start landing immediately to achieve precision landing. The DJI GO 4 app will show a terrain feature mismatch prompt if matching fails.
Precision Landing performance is subject to the following conditions:
a. Home point is recorded upon take off, and cannot not be refreshed during flight.
b. Aircraft must take off vertically. Take off altitude must be greater than 10 meters.
c. Home point terrain features remain largely unchanged.
d. Home point terrain with no distinctive features will affect the performance.
e. Lighting conditions cannot be too light nor too dark.
The following actions are available during landing: a. Pull throttle down to accelerate landing. b. Moving the control sticks in any other direction will stop Precision Landing. The Mavic Pro will descend vertically and Landing Protection will remain active.
Hope that clears it up for you.
Happy flying!