As for as my experience with GPA's are, the only way you can get a 4.00 in High School is through strait A's and anything above it is the result of a extra boost with AP classes. I'm not sure how they weight Middle School GPA's though, it might be heavier since they don't really have an impact on anything. [Where as HS numbers affect the ability to transfer/get into certain colleges ect]
Um.. Well, it depends on what GPA scale your school goes by... Most are 4.0 scales I think, at least mine is. But yeah... on a 4.0 scale you would usually have to have some kind of an honors class to get above a 4.0 and even then it'd be at least mostly As. I'm not really sure how it works in middle school, I never payed attention to it in middle school and you don't really have to lol but as a senior in highschool now I get mostly As and I've got a 3.87 GPA and that's with some honors and APs, so... Maybe there's some kind of a difference? I dunno.
What do you mean you're not an A student if you have a 4.113 GPA in your middle school? Usually a 4.0 GPA means you have straight A's.
Also I was under the impression that GPA was calculating by taking the total number of grade points earned (on a typical 4 point scale, an A = 4 points, a B = 3 points, a C = 2 points, a D = 1 point, and an F = 0 pints) divided by the total number of units taken.