TL;DR
At this stage, the project manager's job is to provide a framework for the companies to address scope, and to estimate the budget and resources needed to deliver that scope. That's it! In situations like these, questions of fault (unless of course it's yours) are really outside a project manager's scope of responsibility.
Rather than assign blame, or attempting to shift the burden to the customer, you should:
- Communicate effectively with your organization (and possibly the client) about the problem.
- Identify one or more potential solutions to the problem.
- Recommend a solution to your senior management, who can then work it out with the client.
Each of these action items are discussed in more detail below.
Communicate Effectively About Problems
Acronyms can cause communication problems, but rarely solve them. Most of your post is a confusing mishmash of acronyms, and does a poor job of communicating about the real problem. So, let's fix that first. Your meaningful facts are:
[T]he statement of work (SOW) simply says that the software will support "reporting".
[O]ur business requirements document (BRD) describes three reports that the software needs to produce.
[T]he client is asking us to create six additional reports and says that it is covered because the SOW says that the software will be used to produce reports.
In summary, the statement of work that defines the scope is vague, the business requirements document may or may not have been written in collaboration with the client, and the client is asking that the project cover six reports instead of three.
Analyze the Problem Accurately
Now that we've identified the actual issues, let's see what that really means for your scope and your process.
- Your company is clearly at fault for the vague scope in the SOW. Your contracting process should be fixed, but in the meantime it kicks responsibility for defining the scope of reporting down the road to some other document or process within the project. This may or may not be your business requirements document.
- When you say "our" business requirements document, it is terribly unclear who the BRD owner actually is. Were the requirements written by the customer, or solicited from them, and then incorporated into the project by the project leadership? Or did your project team create this document, and perhaps do an incomplete job of capturing the full set of requirements? This matters a lot, because in the first case the client defined a scope that they are now exceeding, while in the second case your organization used a vague SOW followed by an incomplete set of requirements to define the scope. If your project team failed to capture the requirements accurately, that would again be your company's fault.
- The very existence of the question presupposes that the reporting product isn't easily extensible. If it were, this would be a minor issue that didn't involve a significant budget or cause concern for two separate management teams. So, there's either technical debt, a lack of a robust implementation, or there are complexities about this reporting requirement that were not captured well by the project.
- This is a question of both project scope (e.g. are the additional reports included in the agreed-upon work?) and liability (e.g. who is at fault for miscommunication, scope creep, or budget overruns). This is a question for senior management (and possibly the lawyers) on both sides to answer, rather than strictly a project management question. To the extent that the project manager should have either identified the vague SOW as a risk, or worked to ensure that the BRD was accurate and complete, there is certainly plenty of blame to go around. However, the real issue is who pays for the additional project costs?
At the end of the day, the first three questions are about assigning blame, and don't really help outside of a courtroom if your contract dispute gets that far. What really matters is how you salvage the project, the customer relationship, and avoid vast cost overruns.
The Pool of Possible Solutions
First of all, forget how you got where you are. Fix that another time. Focus instead on how to collaborate with the customer to find a satisfactory solution that meets:
- the client's expectations for a working product, and
- your company's need to fund any additional work.
In no particular order, your project will eventually do one or more of the following:
- Cry "mea culpa" and do the remaining work at no extra charge.
- Use the experience to improve the contracting, budgeting, estimation, and requirements-gathering processes in the future.
- Collect new reporting requirements and add them to the project with an eye towards minimizing any additional costs while still delivering expected customer value.
- Collaborate with the customer to find an equitable solution.
- Collaborate with the customer to redefine the scope.
- Collaborate with the customer to renegotiate the budget.
- Sic the contracting principals on each other to hammer out a mutually (un)satisfactory solution.
- Lawyer up, and go to court over who was right.
There may be some variations on a theme that I haven't covered, but in general those are your pool of options. Some are definitely more palatable than others, but it's really up to senior management to pick the set of options, not the project manager.
Recommendations
Personally, I'd recommend the collaborative approach whenever possible. Your goal should be to deliver as much value as possible without eating excessive costs, while the client's goal should be to get working software that meets their needs without expecting free work or souring a relationship they may be counting on for long-term support of the software they're paying your company to write.
In a perfect world, this issue would never have arisen. Since it has, you want to explore the art of compromise so that both parties can walk away content if not happy.
In an agile shop, I'd just treat it as an iterative extension of the work already done. In a waterfall shop, I would:
- Regather the requirements.
- Get sign-off by the client and your development team on the new scope to ensure everyone is on the same page.
- Estimate the effort and cost associated with the new scope.
- Let the executives of both companies earn their 400:1 pay by hammering out who's going to pay for the additional scope.
At this stage, the project manager's job is to provide a framework for the companies to address scope, and to estimate the budget and resources needed to deliver that scope. That's it! In situations like these, questions of fault (unless of course it's yours) are really outside a project manager's scope of responsibility.