They need some way to validate things, and it turns out if the number isn't exactly the same when they run their samples they don't trust any of them. For at le

They need some way to validate things, and it turns out if the number isn't exactly the same when they run their samples they don't trust any of them. For at least some value of them. The founder at the last place I worked at was famously difficult to satisfy because of this. You couldn't even begin to talk about how you were presenting data to him unless you were absolutely sure the numbers in your mockup were correct. He just couldn't see past an "incorrect" value when dealing with faked data ...