This looks like a font issue.

For the slash, Finale uses the font selected for the Chord Root = the ‘F’ in F7(#9).

Go to Document Options - Fonts

In the pop up menu Chord, what font is selected for ‘Symbol’?

Thanks, Peter, but see below, how come the Slash and the bass root are nicely shifted or positioned below? Is there a way to manually position the slash and the bass note?

1) This second example looks like another font than in your first example.

What font is used for ‘Symbol’ in this second example?

My guess is that your first posted example looks so bad because of the font.

What font is used in your first posted example?

2) In your second posted example (with a better font), the first chord symbol - F/G - has the Alternate Bass positioned ‘After Root’.

The second chord symbol - Bb7(#9)/Ab - has the Alternate Bass positioned ‘As Subtext’.

Thanks again Peter, I found the solution here: Change Chord Assignments (finalemusic.com)

I'm using my own chord font: NorChanges, I will need to tweak the slash look.

Now it looks OK

And so another self-serving ad slips in, this time masquerading as a post.

MIKE ROSEN, PLEASE, if you've nothing good to say, keep your opinion to yourself, I will continue posting my queries, ideas and my designs, and this is not to promote my works, maybe you don't know how many Finale users have used my fonts since 2005, and how many of them were glad to use my legacy fonts and my new engraver SMuFL fonts. Even MM team has all my fonts for test if they think like you that I'm a spammer and I need to be banned they would do it at a glance.

You can keep tracking me and ask for banning me, et cela montre absolument que vous êtes peut-être un malade et vous devriez voir un psychiatre. Who do you think you're? Mais quel fou!