Do + and - matter

My public high school has a plus and minus grading system ie. A+ A A-

Does it matter that much if I lets say get a B compared to a B+? I heard most colleges recalculate it as 3.0 regardless if it’s a B+ or B-. My school does factor plus and minus into gpa like A+= 4.33 B-=2.67, but since colleges recalculate gpa it doesn’t matter?

Also my school has a tough grading scale(it rounds down too): A=100-93, B=92-84 92.9% still a B+…

I have a copy of my transcript and it does not list the percentage you got but it does list the plus or minus.
However on the bottom there is a legend that shows the grading scale like this A=100-93, but it doesn’t show what percentage you need for an A+, A, or A-, it just says A=100-93.

Yes most colleges calculate GPAs like that. A is an A, B is a B, etc.