Question about Bosch Home & Garden EasyRotak 36-550

Yes, exactly. This is the only way to do it. Loosening the lower wing screws does nothing. The unit works well for us.

You have to loosen the grey wing nuts in the middle section of the spar. This screws on the upper part of the spar. It has two holes, depending on how you screw on the upper part of the spar, you have 3 positions of different heights. The height is not infinitely variable.
Have fun mowing the lawn!