The lead target came first. The customer number came later.

A plan started with the media budget and a lead target because those numbers were easy to produce. Nobody had worked out how many customers the business actually needed, how many qualified opportunities could create them, or where people usually dropped out. Start at the business result, translate it into customers, work backwards through each stage with explicit assumptions, then calculate the contacts and budget required.

Do not invent the top of the funnel. Calculate it from the bottom.