I agree. If you're an executive, you get pitched every day with stuff that will "improve your bottom line by 20%". Most of those numbers are smoke and mirrors. It's hard to decipher fiction from reality, which requires often a detailed understanding of how the number was calculated, what other effects may have been present, whether there was an impact with other customers as well (to prevent cherrypicking randomly favorable results), etc.
Execs are busy and it's a lot of work to understand whether that number is legit or not. In response, they will be jaded to your claims of bottom line improvement.