Not sure I understand your second sentence, it might be saying what I am about to write. From reading several articles on the issue, the EU seems to demand that the slow-down in production be shared equally across orders. This puts AZ in a pickle: it would then mean they are not only breach of contract with the EU but also UK. Hence, they publicly reiterate the "first come first serve" argument which resonates well in the UK media and rallies support (I think AZ is pitting EU against UK in all of this). I do not believe the "first come first serve" principle is how supply chains like this usually work though. Totally not my field of expertise, but hearsay from some friends working in supply chain management.