Build the number from the deliverable
Start with what it costs you to make the video well, including time. Add a fee for the audience you are borrowing. Then add more if they want whitelisting, ads, exclusivity, or a long usage window. CPM math (a price per thousand views) is one input for a live or integrated spot. It is a bad sole input for a polished video they will run as an ad.
Write the number down before the call. Discounts are for a smaller scope, not for someone who sounds nice.