To get to 220x, you have to use the shorter plastic lens guard. Mine focuses at 220x with the guard about 1cm above the target.
The focal range is a function of the optics. I haven't seen any other microscopes that allow long-distance focusing, so I can't comment on that.
If you are not satisfied, please feel free to email firstname.lastname@example.org
with a link to this thread and ask to return the microscope for a refund