Is his expectation fair.

[chris.biker]

I think that you can't use this contraption for anything.

The reason is that every car jack I've ever used and own all have a lable stating that they are for lifting the vehicle to a safe height to insert permenant jacks only and the vehicle should not be worked on whilst supported only by the trolley jack.

Unless this lift has some way of fixing it in position after it is raised by the trolley jack I wouldn't want to use it.

I agree with you, I had not looked closely enough to notice that this bench did not have a locking mechanism to lock in place once it is at the required height.