This may explain a little better … a picture paints a thousand words, etc.
What your POI will create is the 5° for WP1, and 90° for WP2.
At the mid-point what you need is 20°.
But the Mavic will turn at a constant rate so that, at the mid-point, it will be at 42.5° …. half way between 5° and 90° … and not pointing at the POI.
Edit: … and, my inserting method … you can see they keep the POI more central.
