When selecting my sectors on the campaign builder/mapping screen, why is the cost cheaper in the summary at the top of the screen vs. the individual sector price?

Ah we can explain this, currently, all sectors are labelled and displayed based on their individual sector volume/cost. The higher your total volume goes, the cheaper your rate per thousand becomes. Our system is busy in the background ensuring your cost is accurate and reflects this. In our world we refer to this as Volume Related Discount. So the accurate price is in the summary screen.