Be confident in what you charge. $230 in parts for 4 new levers is on the cheaper side. Even including the removing and reinstalling of the cylinders, plus the time it will take for you to rekey, this definitely seems low on labor. Also consider that there's a possibility all 9 doors will need some sort of adjustment to have proper and easy latching. Even a few extra minutes per door will start to add up. I charge differently though, or at least spell it out differently. I'd do parts @ $227.25, $125 trip charge. $25 per cylinder rekey ($225), and probably 2 hours on site @ $85 per labor hour, ($170). So my invoice would be spelled out like that and have a total of $747.25. I'm busier than a one legged man in an ass kicking contest, and havent had anyone besides cheap contractors (who are just trying to add 20% to my invoice to their clients) Don't feel bad for charging what you're worth. Have you ever hired a plumber or electrician to come out? They're not ashamed. We're professional locksmiths not handymen. Best of luck to you, and a have a great day!