I have only sparing used support services. I am torn between the need to have it working consistently every day and additional costs over and above the basic fee, which I feel is reasonable.
Extensive support calls/internet that require more than a 99213 (15 minute) may deserve a service fee IFF they are not AC related. This can be somewhat touchy at times, but may allow a somewhat more beefed up support service. I again, have not needed much help, so per service without a base charge might have been acceptable (I prefer the Guardian Angel over me though)