In the future, if asked by someone to do a UL commercial system, having had this experience, you might want to consider taking the position of "advisor" and educating the consumer of all of the possible "pitfalls" , installation expenses, paperwork, and on-going expenses after the installation that are propegated by the insurance companies and UL leigon. Tell them you will give them a quote on a great system that's not UL and once they've gotten all the quotes from the UL installers, have them get back to you for a "better route" to take. I've gotten a few takers in my time on this basis simply because I was deemed the knowledgeable "straight shooter" of the whole lot. As I said, most alarm companys who do UL installations wouldn't think of offering anything other than a UL system.
With all that you've learned on the subject, you just might want to do a little write up on all the facts and put it in a folder somewhere. The next time you get asked by someone you'll have a crib sheet to work from. Just copy all of the posts in this thread, for instance.