One thing I noticed in the video is that his car did not have air struts.
So having read your comment again I remembered something: a few years back a guy on this forum had a problem with his 430 - the ride height sensors failed meaning his car would not rise to the correct level - he decided to buy the sensors and have them replaced at his local garage - the garage managed to fit them but could'nt get the car to rise - he then had to have the car recovered to Lexus to have it recalibrated.
So thinking about your situation - if the struts need to be removed then there may be some truth in what the garage is saying
So I think you will need to speak to a few more people/garages to gather some more information