<p>Our school does fractional points for +/-s, but not as granular as your post. Examples at our kid’s private independent school:</p>
<p>B- = 2.7
B = 3.0
B+ = 3.3
A- = 3.7
A = 4.0
A+ = 4.3</p>
<p>Who are you trying to prove it to? Are you trying to talk your school into using a more granular scale?</p>