I looked at your thread in the Adobe forum (great screenshot, very helpful!) and you got the right advice there. But I think you're still missing some important techniques.
You need to create a specific paragraph style for your TOC entries, as recommended. That paragraph style should include the correct tab stop(s) and the leader dot style for the tab … all of this is selectable in the Paragraph Style Options dialog box, in the Tabs panel.
If you want to change the font or color or tracking of *just* the leader dots, then you need to 1) Create a character style for the leader dots; and 2) Edit your new TOC Entry paragraph style so a Nested Style automatically applies your leader dots character style when it encounters a tab, and only applies it to that tab character.
Test out your new TOC Entry style on some sample text to make sure it's right. Then choose the name of that style in the TOC dialog box, in the middle section (Style heading section, the Entry Style: pop-up menu). Right now you have it set to “Body” per your screen shots.
That should fix your “update TOC” problem.
AM