An outcome is beginning to take shape. Things are looking good. But they can be improved. The effort is to identify the weaknesses and to seek to put them right.
The effort should be a combined one by both parties. It is in the interests of both parties to have an outcome that will work.

The outcome needs to be looked at from all angles and take into consideration all possible circumstances. How does it stand up?

It may now be a matter of problem solving or further design effort. Can the benefits be enhanced? Can things be made more simple?