I have been working with the font supplied by the RIBBS site for over a year. I had issues with the USPSIMBCompact font right away. In certain cases the barcode would go "missing" at random on a number of printed pieces. (still no clue as to why...), but to fix the issue, I began using the USPSIMBStandard font and have not had any issues with this font.
I am attaching images that show how I set up my rule. This may be of help to some of the newer users.
The first image shows the field in the csv file, "FATD" format.
The second image shows the rule I created to use the data field, format the text, and apply an automatic amount of leading to the barcode line.
The third image shows the usage of the barcode rule in the text editor.
I format the endorsement rule the same way, including the font and leading into the rule. That way I don't have to change any fonts in the text editor during layout of the mail piece. This saves me a lot of time in the creation of each mail piece.
Hopes this helps.