tedster - 6:06 pm on Feb 26, 2010 (gmt 0)
hasimsg, yes - I've been noticing that more in recent weeks, too. Or you add a + sign before a word and total results goes up.
It's some artifact of how the SERP is constructed - possibly that some SERPs (shorter phrases that use no advanced operators) have been cached in a way - that is, the identifiers for the individual URLs to be included are pre-cached. The recent appearance of more of these discrepancies signals some kind of shift in Google's technical approach, but the specifics are not clear.