¿Por qué Apple TIme Machine informa de la transferencia de tantos datos?

Apenas he utilizado mi ordenador, pero me he dado cuenta de que Time Machine ha transferido 2,7G de datos inmediatamente después de ejecutar lo siguiente:

mbp:~ alexus$ time tmutil compare
- 181B                          /Volumes/Time Machine Backups/Backups.backupdb/mbp/2013-06-24-124026/Macintosh HD/.com.apple.backupd.mvlist.plist
!         (mtime)               /Library/Application Support/Norton Solutions Support/Scheduler/SchedulerAux/com.symantec.symsched
!         (mtime)               /Library/Caches
!         (mtime)               /Library/Preferences
! 4.5K    (mtime)               /Library/Preferences/com.apple.TimeMachine.plist
!         (mtime)               /System/Library/Caches
! 10.5K   (size, mtime)         /Users/alexus/.bash_history
!         (mtime)               /Users/alexus/Dropbox/1Password.agilekeychain
! 512.4K  (mtime)               /Users/alexus/Library/Application Support/Google/Chrome/Default/GPUCache/index
!         (mtime)               /Users/alexus/Library/Calendars
! 2.1K    (mtime)               /Users/alexus/Library/Calendars/11367463-CB25-4E29-A258-A374E54A1ADD.caldav/Info.plist
! 3.2K    (mtime)               /Users/alexus/Library/Calendars/1245EE97-E221-42E3-B4AC-FE15BB0B9E38.caldav/Info.plist
!         (mtime)               /Users/alexus/Library/Preferences
! 856B    (mtime)               /Users/alexus/Library/Preferences/at.obdev.LittleSnitchNetworkMonitor.plist
!         (mtime)               /Volumes
!         (mtime)               /private/tmp
!         (mtime)               /private/var/db
! 1.4K    (size, mtime)         /private/var/db/.TimeMachine.Results.plist
!         (mtime)               /private/var/db/ConfigurationProfiles/Setup
! 3.0K    (mtime)               /private/var/db/com.apple.TimeMachine.SnapshotDates.plist
!         (mtime)               /private/var/db/mds/messages
! 32.0K   (mtime)               /private/var/db/mds/messages/se_SecurityMessages
!         (mtime)               /private/var/db/mds/system
! 0B      (mtime)               /private/var/db/mds/system/.fl8E6EFC6C
! 0B      (mtime)               /private/var/db/mds/system/.flCF600F4B
! 0B      (mtime)               /private/var/db/mds/system/mds.lock
! 49.6K   (mtime)               /private/var/db/mds/system/mdsDirectory.db
! 4.5K    (mtime)               /private/var/db/mds/system/mdsObject.db
!         (mtime)               /private/var/rpc/ncacn_np
+ 0B                            /private/var/rpc/ncacn_np/lsarpc
+ 0B                            /private/var/rpc/ncacn_np/mdssvc
+ 0B                            /private/var/rpc/ncacn_np/srvsvc
+ 0B                            /private/var/rpc/ncacn_np/wkssvc
!         (mtime)               /private/var/rpc/ncalrpc
+ 0B                            /private/var/rpc/ncalrpc/NETLOGON
+ 0B                            /private/var/rpc/ncalrpc/lsarpc
+ 0B                            /private/var/rpc/ncalrpc/srvsvc
+ 0B                            /private/var/rpc/ncalrpc/wkssvc

-------------------------------------
Added:         0B
Removed:       181B
Changed:       623.9K

real    15m4.257s
user    0m56.826s
sys 2m7.513s
mbp:~ alexus$ 

¿Por qué dice 2,7G entonces?