Checksum: “found by guessed name” – What?

I have the following checksums: Mac OS X 10.6.4 Combo Update found by display name or checksum and verified in 18 seconds Remote Desktop Client 3.3.2 found by display name or checksum and verified in less than one second AirPort Base Station Update 2010-001 5.5.1 found by display name or checksum and verified in less than one second Security Update 2010-005 for SnowLeopard found by display name or checksum and verified in 1 second Java For MacOS X 10.6 Update 2 found by display name or checksum and verified in 1 second Snow Leopard Graphics Update 1.0 found by display name or checksum and verified in 1 second Safari 5.0.2 Leopard-SnowLeopard found by display name or checksum and verified in less than one second Server Admin Tools 10.6.4 found by display name or checksum and verified in 4 seconds Office 2008 12.2.0 for Mac [u][b]found by guessed name[/b][/u] and verified in 13 seconds Office 2008 12.2.6 Update found by display name or checksum and verified in 17 seconds Why is my "Office 2008 12.2.0 for Mac" installation program being found by "guessed name" and all the others are being found by "display name"? "Office 2008 12.2.0 for Mac" passes the checksum process but why is it saying "guessed name"?