Knowing X get Y% discount would give you the opportunity to ask for the same Y% discount. Not just AWS, in enterprise world the service provider will always make the % discount a secret and you can’t tell anyone else.
Almost universally, you get taken more seriously when you demonstrate you understand the exact quantity of leverage you have.
“I know this is possible because we had it at X” is a lot different conversation than “We want X”. Your leverage is even worse when X is nowhere near reality (in either direction).