For your information: In an old house, an electrician usually faces a grab bag of peculiarities. No one here in the forum, and that is for sure, can even remotely tell you whether the offer is justified since you haven't made it public. The electrician is liable for the entire system as soon as he makes a significant change; this also includes the E-Check. In the worst case, he might spend days searching for flush-mounted boxes in which phase errors are built in.
If anything, the electrician's offer will only contain the expected scope. Surely, if he isn't completely foolish, he will reserve the right to charge for unexpected work beyond the offer. I also have a (very) old house and had a large part of the electrical system replaced or renewed there a few years ago, including a new (about 4 times larger) meter cabinet. After several companies inspected the meter cabinet and left without an offer, with hands covering their faces, I finally had to find a creative way to get it done. About 6K and many dozens of hours of work later, about 70-80% of the electrical system was at a tolerable standard :rolleyes:
Of course, as always, just my humble layman's opinion without any guarantee.