I don't think Suzanne's TOC tips include the issue the poster is having. Microsoft have been tweaking the behaviour of tab stops with regards to TOC levels and there are differences between Word versions now.

In older versions of Word (from memory pre-2013), you used to be able to bring the right indent in a bit and put the tab stop for the page number out beyond that. You could do this to make any multi-line TOC entries avoid having words that ran into the vertical line of the page numbers.

In current versions of Word (excluding Compatibility Mode), this cleaner look is not possible. For starters the GUI stops you moving a tab stop on the ruler beyond the right paragraph margin. If you use the Insert Tabs dialog to place a tab beyond the right margin, the page number stops at the paragraph right margin instead - this did not happen in earlier versions of Word.

The question raised by the OP relates directly to the 'new' Word behaviour so they have to think about where they want their page numbers to align. The alignment they are seeing looks like the TOC 3 style has a right tab somewhere beyond the right margin setting of the style (and Word is displaying the newer behaviour of ignoring that tab in favour of the right margin setting). They are not seeing this with TOC 1 and TOC 2 because the tab stop is aligned at a smaller number which either aligns with the right margin or 0.5cm inside the margin depending on their margin size. This is why the TOC 3 style number alignment is varying depending on margin size but TOC 1 and TOC 2 aren't. I hypothesize that reducing the column width further by making the right margin even bigger (eg 5cm) would get all their numbers aligning again because of this behaviour.

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Andrew Lockton
Chrysalis Design, Melbourne Australia