I think the short answer is that it isn't a font. It is a drawn element. This is because you may have something like this:
What 'font' can be used for the upper and lower dimensions? If a dimension contains elements on multiple lines, you cannot create parentheses using a font. So, rather than have a special case for one line dimensions, the same algorithm is used to draw them for all styles, which sometimes leads to less than optimal results.
If you follow standards Jim, you cannot have the dimensions you show. Reference dimensions, auxiliary dimensions or redundant dimensions, call them what you will, are additional info to dimensions which can be found elsewhere. You don't put tolerances on, nor are trailing zeroes put after the decimal point.
ISO 129 says, "Auxiliary Dimensions in drawings are for information only. They shall be given within parentheses, and shall never be toleranced."
It probably says as such in ANSI standards too.
Perhaps SW is mistaken by providing the "Add Parentheses" button.
If you go into tools>options>document properties you can change the way your drawing sheet will display dimensions. (won't change format of dimensions already on the sheet). You can change the setting for basically everything on the sheet through document properties. I'd recommend getting it the way you want and then creating a document template (or multiples there-of). Works the same in part and assembly files, so set up templates for them all.