is there a warranty on the product? i have a friend who does this as well, the spray will last 3 years according to them and they give a 2.5 year warranty on it. it does the same thing.....remove odour, kill bacteria, fungus, dust ,smoke smell etc etc. apparently it also can be used on building walls.
personally the 2.5 yrs warranty is the strong point and the fact that the car's interior wont smell. going to try it out soon.
maybe a group session we can get it cheaper