Here is an example of a "ribbon dim" change... compared to a section dim.
The .6667 was entered as 2/3. The value only takes on the value of the number of places designated.
Unlike the dimension added in a section, where the value 1/3 remains .33333333333333 and displays as .3333.
This really is a problem with me. Anytime I use a arithmetic operation for a value, I expect that value to remain to the maximum number of places without having to re-edit this value later. If I go in and change the properties of the extrude depth dimension, I can set it to 4 places, rounded, and use the same calculation of 2/3 and it remains .666666666667 and shows as .6667. Now when I edit this value in the graphics screen, the popup shows .666666666667 as it should have in the 1st place.
I have tried every way to change this to see if it changes after save. I cannot reproduce what you are saying.
Make sure that the properties of your dimensions are set to rounded. If not, it will change the dimension to the number of digits specified.
Example of Ribbon Dim...
Section Dim
