I run a service carpet cleaning co. I have hired a few sales persons on a 18% commission pay per sale. I have one guy going after large prop. companies and making some fine progress. Some of these company's have many apts. If I pay him on his initial sale and first service to this company , which may be only a few apts at a time. while at the same time this sale may lead to much more business. How do I keep this type of sale more attractive and fair to my sale person?