You might want to see http://word.mvps.org/FAQs/Formatting/SettingTabs.htm

When you set tabs in a paragraph, they apply to that paragraph and any
others you subsequently create by pressing Enter. That is, the formatting is
preserved in new paragraphs until you change it.

After text has been entered, if you want to change the location of existing
tabs or add new ones, you must first select all the text you want affected.
In this case, you shouldn't add new tabs (which will just make a mess);
instead you should move the existing ones. The easiest way to do this is to
drag them on the ruler.

--
Suzanne S. Barnhill
Microsoft MVP (Word)