A 27 is the same 27 no matter where you go. It helps put your GPA in context which is why it's used in admissions. It's the same reason for why step 1 is so important. A 27 from Harvard is not better than a 27 from a community college.
This is great in theory. It's not true. And by the way, not all GPAs are created equal. And the Easter bunny isn't real. And the tooth fairy? Fake as well.