I think everyone wants to answer that.
One of the big problems with cost estimates is that they have to be done years ahead of time. Inevitably, the numbers have changed by the time we're ready to carry out the project. For example, sometimes we have to figure out the cost of a project that will be completed five years down the road. We base the estimates on the numbers we have at the time, but the numbers tend to change afterwards.
It would be helpful if we could provide a much rougher estimate and indicate, for instance, that the project was going to cost somewhere between x and y dollars. Once it came time to actually carry out the project, we could provide a much more exact number. That would help not only DND, but also our colleagues at the finance department and Treasury Board.