I agree strongly. You shouldnt have to give any discount if you do quality work and charge a normal rate. I like to give a discount but its not money. say you had a house and driveway wash with a price worked out and noticed a tiny wood shed or something that was not part of the deal if it only takes 10 min to do and really cheap on chemical get er done and mention it to the customer. Be like hey sir I noticed you had a dirty old shed over there that was not part of our deal but i Hit er anyway and i hope you dont mind. thats when they are putty in your hands.
I think the service you provide is worth what you charge and you should keep it that way. Going a little above and beyond when it bennefits you is cool but people start to expect things when they are given. Its like the saying give them an inch and they take a mile, its more like give them a mile and they wont want a lousy inch. Welcome to the forum, alot of good smart guys around so be sponge like and soak up the info, these guys have been around for a while through thick and thin.
ps. fill in your signature and they will be more inclined to help. And we know your not a scamming bot or a hack.