It may be a n00b question but can someone please explain on the ceiling drop range? Is that basically how tall the garage racks will be installed, as in how low they'll drop?
I think you've got it right. As I understand it, the drop range is the adjustable height range in which the unit can be positioned. So, for example, if you installed the racks above your garage door, you could measure the clearance you would need to safely allow the garage door to open.
Most people will probably buy the unit with the maximum height range available. However, those with smaller garages might have limited space for installation.