Mysteriously Changing Line Spacing

[leohaas]

Using Word 2003 on Windows XP.
Created a template called xxx.dot, attached it to both Document1 and Document2.
Definition of Normal style in template is:
Font: (Default) Arial, 12 pt, English (U.S.), Left, line spacing: single, Space before: 6 pt, After: 3 pt, Window/Orphan control.
When using this in Document1, 33 lines of Normal style fit on one page (8.5x11"; 1 inch margin left, right, top, bottom).
When using this in Document2, only 28 of these lines fit (same page settings)!
How is this possible? In Document2 this style (and of course all styles based on it) take up more vertical space than the same style does in Document1!
Am I missing something here? Is there a document-wide setting that overrides (or multiplies by a set number) what I specify in my style definitions?