[gadders]

Normally on a fixed bid project, the consultancy hopes for change requests. That is where they make a lot of their margin.

At that stage, you have the client company over a bit of a barrel. Unless they want to throw the consultancy out and start the bid process again.

[zdragnar]

Smaller consultancies rely on good relationships for recurring projects and / or referrals, so I haven't seen this behavior as much from them. That said, I do not think it is uncommon for a consultancy to try to make up losses on the original fixed bid with higher margins on changes or future work. It really depends on the people running the show, especially on the sales side of things.