Numbering in Word 2007

I have a large (over 150 page) document that has paragraphs followed by
numbered lists. I'm using one of the canned 2007 Styles for the documents
overarching look.

I went into the Numbering Library and modified the Numbering format so that
each level of the multilevel list stepped in appropriately - 2 is flush left,
2.1 starts under the starting text of 2, 2.1.1 starts under the starting text
of 2.1 etc. This does make the latter numbers have small text areas, but it
gives the look I want.

Now, I have a problem. The document is not using the numbered list style I
selected any longer. If I start a new list in the document, I have to
reformat it by "Format Painting" over it after starting it. If I change an
existing list - the formatting goes haywire with different tab stops and
indents.

What am I doing wrong?