AX rounds to 2 throughout most aspects of the system. You can extend the EDT to greater than 2 for units, a debate that always causes issues. Essentially if you do this the physical change is relatively simple but because of the depth of the code, calculations and roundings Microsoft suggest that you parallel test this for 6 months on all processes and validate all calculations, which is a lot to ask, but without doing it whilst encountering some risk, MS can turn around at any point with any issue you have and point out that the EDT extension is probably the cause and not support you on the issue 