Decrease Style Font Size

Under.zip (XStyles) "DecreaseStyleFontSize" - Changes the font size in the selected paragraph style by -0.5; resets to 12 at zero.
Typically I have several block of MacroText styled paragraphs[ in a document; within one block a line wraps around. I want to reduce the font size so that the line does not wrap around, and I want the Macrotext blocks to be consistent in appearance.
I need to change the font size of the paragraph style.
If the font size reduces to zero, it will restart at 12 points.
See also the macro "IncreaseStyleFontSize".