it seems to me that you would want to at least confirm to yourself that you actually improved your skills by attending a training class (whatever skills are important to you to improve). granted, you likely won't improve in just one day at the range, but if you practice and repeat drills over time to improve your skills, you should be able to show a positive change.
i like going to the range as much as anyone, but if i'm going to pay serious money to someone to take a class, i'd like to improve some skills as a result of that class and my own practice after the class.