Word heading numbering

Anyone who has used Microsoft Word for any length of time will know that the heading numbering is fundamentally broken; a fact that is unforgivable, given that WordPerfect 5.1 had it pretty much sorted in 1989.

One bug that I've frequently struggled with is where subsections look like this:

Appendix A Name of appendix

A1 Sub-heading 1

A1.1 A paragraph.

A1.2 Another paragraph.

A1.3 A third paragraph.

A2 Sub-heading 2

A1.4 Why?

Getting that third level heading to number correctly is nearly impossible. Ticking the "Restart list after:" tickbox in the "Define new Multilevel list" dialog doesn't work. Sometimes just typing "A2.1<Tab>Why<Enter>" provokes Word to try to be clever and format the heading as such; then it's an easy matter to update the appropriate Heading style to match the selection. Sometimes that doesn't work. Sometimes going back and defining all the relevant heading styles from scratch works.

Now I've found a new way. I noticed the "Click level to modify" list in the  in the "Define new Multilevel list" dialog included A1 but not A2. That inspired the following.

1. Format the paragraph in the same style as A2; it'll become A3.
2. Demote the paragraph (possibly by using Tab, but you may need to go into Outline view to be sure).
3. Now the numbering should include "A.2" and possibly a lot more if, like me, you're using low-level heading styles like H6ff. [Note to self: that's probably a bad idea.]
4. Now you can edit the numbering in the "Define new Multilevel list" dialog.

It shouldn't be this difficult!