Sorry dude I was just being funny. But if they are asking you to bring it up to code you can either do it T and M or spend and hour looking over the joint and giving them a flat rate for the whole job. It would help if you gave a bit more info on the type, age of the home. From my experiance and given the large amount of older homes in my area you can really come up with a big punch list, and I mean big. I was asked a few months ago to do something similar to a home in Newark NJ and the final bill came to around 4200 bucks. I gave them a flat rate and to my surprise they gave a sigh of relief.Granted it took me a few days What might seem like alot to you can be a drop in a bucket for some people.
And if they want you to bring up to code thats what they want so do it. I personally would tell them that you will chage them 100 bucks or so to look it over and come up with a complete list. And if you feel like being a pal tell them if they decide to go with it you will deduct the 100 bucks. ( personally wouldnt but some guys do) IMO looking over the house and diagnosing the problems is a honest service that you are providing them, so why take it back? Any hooo good luck let us know how it turned out. But keep in mind There might be nothing wrong I really dont have any info on the home so you still need to charge for your time.