I would be will to share my estimte form with you guys if you like
I would be really interested in seeing your form if you are still interested in sharing.
I also bill clients for updates, but I require a 1/2 hour minimum. Even if it is just a couple of changes it does take awhile. Not only do you have to make the updates, but you also have to email the client, make phone calls, create invoices, mail them ect....
I've found my half hour minimum usuall catches that extra stuff.
Of course it's always good P.R. to throw a couple freebies. I have a client who has had me make over $300 worth of changes to his site in the last 4 weeks. If he emails and wants one single paragraph added or deleted (or something else small) I'm going to throw it in as a freebie.