If you don't get a lot of replys from service agreements, it may be all the requlations and laws of some states and insurance underwriters, make it difficult or expensive to offer them. some states require special bonding before you offer them, and you may also need to pay into a special fund, that along with your insurance companie may have your contract include special clauses for limits of liability, and require you to secure E&O coverages, in most cases you can't just start offering service agreements without good legal service to draw up the agreements.
They are good for alarm and FA contracts. I don't put in either systems any longer but I still have existing in place service contracts that come in very handy at times.