The cost of asking twice
Count how often your people re-answer the same question. Then price it.
Take one week. Every time somebody asks a colleague something that has been answered before, put a mark on paper. Most directors stop counting on Wednesday.
It is not the minutes
The cost is not the ten minutes. It is the decision made on half the picture, the client told something slightly different, and the senior who becomes a helpdesk instead of doing the work you hired them for.
A closed loop makes the second question cheaper to answer than the first.