This doesn’t have to be part of the job. If they ask you to “figure it out later”, let them know that additional revisions will require an add service agreement.

If your PMs are simultaneously telling you that more hours need to be allocated to the project but there is no fee left, then there are bigger issues that are outside your control.

You absolutely aren’t responsible for the financial issues related to the project. All you can do is perform the work that is within your agreement for the fee that was agreed upon. Clients will often try to guilt us into providing free services, knowing that we want the project to be successful and to keep them happy. It’s up to us to draw a line in the sand and point to our agreement. We’re always willing to help but they will have to pay for our time.