Every project is different and has particular characteristics. I think you acquired your ship by a competitive process and that may have been vulnerable. It's also a slow process. I don't know how the requirements have changed since the commitment to a contract was made.
My view is that in this day and age, we have to have a more co-operative view about trying to calculate what the cost is likely to be.
If you want further complication—which you may not like—most platforms cost much more to run in service over their life than they do to buy in the first place. In a way, in looking at the acquisition costs, you're focusing on something that is relatively unimportant. The thing that is really going to take your dollars is looking after it once it's in service. That gets less attention because it's more difficult to pin down.