I've found that the Dovecot IMAP server (also apparently UW-IMAP)
"canonicalizes" subject lines in message lists by reducing all runs of
white space to a single space. This kills the utility of white space
padding in the _SCORE( )_ header rewriting macro in preserving columns for
numerical sorting.
Here's the discussion where this decision was made by several IMAP server
authors (including Crispin):
<http://www.washington.edu/imap/listarch/2003/msg00738.html>
So if you use an IMAP server and you want your scores to line up for
sorting, use _SCORE_(0) to pad with leading zeroes.
