I'm still confused by this and am hoping someone with gradebook expertise (Elena?) can help me to understand and maybe have a conversation about it. I realize now this is not new and the functionality has been around for some time therefore not a bug I suppose. I must have missed this somehow and am regretful for how I have advised my faculty. However the documentation clearly states:
"Overall decimal points
This setting determines the number of decimal points to display for each grade. It has no effect on grade calculations, which are made with an accuracy of 5 decimal places."
Perhaps this is then a flaw in the documentation as the grade and grade letter can in fact change based on how many decimal places one chooses to "display". For example, if the instructor chooses to display 2 decimal places throughout the term and then chooses to display the final grade without decimals at the end of the term, one's grade could go from a 79.99 (A-) to a 80 (B+). Simply from changing a display option.