Applicants who went to the same highschool but have different grading scale on their school report

[1NJParent]

Apparently, similar issues with grading scale exist even in some US high schools, as reported on this CC thread yesterday:

Is a 4.0 a 4.0?

Wow at your school an 89.45 is an A? First, do you not even have A-, but second why do they round that up even? At our high school that is a B+. The lowest A- at our school is an 89.5. An 89.45 does not get rounded to an 89.5, it’s an 89.45 period. That would be considered grade inflation. I do wonder how colleges look at schools on a +- system different though than one that isn’t because you are right that technically a 90 and 100 are no different. I know Michigan calculates a new GPA taking our + and - and unweighting everything and how they remove fine arts and other classes and assign points based on rigor of class etc. Never really thought about it before you made that comment though. Would love to hear insight into anyone former AOs out there that have experience with these different systems.

Posters reported there that a) teachers can be “persuaded” to map different students to different letter grades even though they’re in the same range according to the school’s grading scale; and b) some schools give their teachers the “discretion” when converting students’ “raw” grades to letter grades, not necessarily based on the school’s official grading scale.