Is Parameter RangeFinder Changed Become Sonar Range in Mission Planner/ Arduplane Fw 4.5.7? (While Range Finder is Freeze)

ArduPlane VTOL Plane
1

Hello guys, I am a bit confused when configuring Range Finder for my Quadplane. I just discovered that in Mission Planner, Range Finder1 display will be freeze after about one minute, but I found that “SONAR RANGE” Parameter shows real time actual distance. Is this normal ?? Does it mean that the real distance Altitude used by Mission Planner/Ardupilot is “Sonar Range”. I have not done flight test yet using this new range finder set up. I need help/advice from expert here about this issue.
I attached here display of both parameters.
Any advice is hightly appreciated.
I have tried using Laser Range finder from Lightware SF11C , and also Benewake TF-02 Pro, and both Lildars show similar issue (that 'Range Finder value is Freeze). I use Serial Range finder. I have tried parameter rngefinder type is 19 (Benewake TF-02) or 20 (serial Benewake), but same result.

Thank you.

Range Finder Sonar Range
Range Finder Sonar Range526×721 111 KB

2

Hello @tridge , @Michael_Oborne , @hwurzburg , @Rolf maybe can give advice?
There is no clear information on the documentation about what is the difference?
Thank you.