Values of the decimal places are controlled by the global variables depending on its object type e.g. REAL, DIST, BORE.. & others. If you want to roundup the values to whole number, you need to modify the global variable that controls on it.
Type in the command line to update the Distance format decimal places value: System default value is set to 2 decimal place. !!distanceFmt.dp = 0
Take note that this will affect all of the distance units settings including Measure Distance.
May I know what is your purpose or what are you trying to achieve why need to get rid of this decimal places? There's maybe other simple ways on how to do it if we may know what is it for.
Your request is a bit complicated, you need to modify the aveva default macro programs in order to do this. There maybe other method on how to solve this.
As for my advice, if the default values with ".00mm" does not cause any errors for the Desparam then just let it be as with the default format. Aveva has implemented this units conventions for easy migration of project units settings for example from MM to FINCH.