Yes, basically Ian the two lines are adjusted manually until they form a single line Justin front of the unit.
Then using the remote you can scan the floor for a complete 360degrees if you wish. Wherever the single line separates, there is a rise or fall in your floor. You can mark it so accurately that you can trace the outline of the lump or divet in the floor.
So you can either grind out the lumps or latex out the divets. You can even latex as you scan the floor and watch the lines come together and form one in front of you as you latex. That's what the target is for, it indicates a rise or fall, depending where the lines intersect it.