Jim their thinking will be that they can get it cleaned 3 times a year, but it sounds as though may need it doing 3 times a year.
Trouble is with most commercials is taht they only get jobs done when it's bad then they shop like they are shopping for stationary, pen is a pen, they don't actually give any value to the service you are doing or the carpet as it's no theirs only thing you do get is that you can offer a NO BRAINER job with no problems and apart from a great clean NO disruption and the negatives that may come with it.
Shaun