I don’t think Dynamo does any rounding -
the XYZ ToPoint method is here:
the InDynamoUnits does do a scale though depending on Revit units:
which as has been stated, will create noise with floating point numbers.
If you mean you see the displayed number in Dynamo’s preview as rounded - that is possible, but I don’t think that rounding has actually been applied to the point - it’s just for display AFAIK.
If you see it in Revit, then I’m not sure.