Tech Data Sheet Question

Hi all again, I was told that when your looking at the Product Tech Data sheets on an oil, these numbers can be the original expectations set out by the company the oil should have and not what's really on offer. I have also been told that there can be a huge tolerance variation in the numbers shown on paper. I was wondering can anyone clear this up for me? surly you would thing that the SAE would have strict guide lines for the info sheets and the end result to follow.