Right! It's not that the contractor was incapable of estimating it, but they needed to allocate some of their time to analysing the project. And given that ther

Right! It's not that the contractor was incapable of estimating it, but they needed to allocate some of their time to analysing the project. And given that there are many tasks a developer might have to complete, there'd have to be a priority call over whether analysis on Z was more important than development on X and Y. And when the contractor had the meeting where the product owner was present, it sounds like they implicitly understood this and were happy with the more general estimate.