First, make sure you change the font to JazzCord for the symbol & suffix.

You're seeing "normal" letters for the chord suffix font because those suffix's exist in the document and Finale sees them and uses them. Delete all of the previously created chord suffix's. Then load the JazzCord library. I was never able to get these Jazz chord suffix's to type in correctly, so I go to the chord definition dialog box, click on the "select" button, and choose the suffix I want.

With the chord suffixes in e. g. the JazzText font you can enter a suffix like e. g. mi6/9 by typing the individual suffix characters one by one:

m i 6 / 9

That works because the JazzText suffix mi6/9 is composed of the five characters

m i 6 / 9

But that entry method does not work with JazzCord suffixes because the entire suffix - like e. g. mi6/9 - is one single (big) character in the JazzCord font.

To enter the JazzCord suffixes fast, learn the colon method.

Example: Ami6/9

Type A:0 - and hit Return.

Because of the zero Finale now will display the Chord Suffix Selection where you can choose the suffix mi6/9.

Note the suffix number.

In this example let us say that mi6/9 is suffix #42 in the Chord Suffix Selection.

The next time you need Ami6/9, type A:42.

Thanks for your support guys, I hope in a more comfortably and natural way to manage this tasks in future with Finale