Not taking action until things are already on fire is one of the main reasons why projects often get out of hand – many ERP projects are a prime example of this.
Initially, the customer draws up a specification document – sometimes with contractual conditions – which then gets converted by the service provider into a functional specification document as part of its offer. The project begins, then it becomes clear that the project will be implemented on the basis of the service provider’s terms and conditions. At first discussions about any change requests are not wanted because of the good project atmosphere, milestones get postponed, the solution is not so industry-specific after all, the project costs get out of hand – all this can also happen in an agile project – and the dependency on the service provider becomes bigger and bigger. Either the customer goes along with it or he runs the risk that the service provider stops working – e.g. because the customer withholds payment – and the project is delayed again. Are you familiar with this situation?
The other approach is to actively draft the contract in the sense of a specified project content, clear rules for the procedure and to engage in discussions about in scope or out of scope from the outset. This requires a good contractual basis and professional project management in the sense of tight project controlling.
You can find more details here. (in German)