I agree with Evan (again).

The only reason to say "32" is because you do it the same way every time with the same kit and "32" means the same thing to YOU every time. You actually have NO idea if it's 30 or 40--just that it's between them. You can be no more precise than that, and, since it's a log scale, halfway in the middle does NOT mean "35".

I repeat the test 2 or 3 times just so I know which side of the line I'm on. I guess "32" because it's a lot closer to the 30 line than the 40, or "38" for the same reason it's closer to the 40. But even that is no more than a convention.