Absolutely the most uncomfortable lifting chair I have ever had, I am not a mathematician but have been in Mechanical Engineering all of my life and the Geometry of this chair is totally wrong. I have looked underneath this chair to check this and it is full of mistakes. Unfortunately I will have to put up with it and hope to do some changes. I can't even sit in it in a normal position ( reasonably upright and have to go to a reasonably tilt on the chair to sit reasonably upright, and even then it feels that you are sitting on pieces of slats or springs.
I only hope that when I am due for a new chair it is sourced from somewhere else. I will have to get a fairly solid cushion for it to be able to sit comfortably.
I was fully measured for this chair and these measurements were completely ignored .