Update manager shows incorrect download size

[Vishnu V]

Update manager shows incorrect download size.
It says 45MB of 36.1 MB dowloaded (Google chrome update)

Screenshot attached

ProblemType: Bug
DistroRelease: Ubuntu 12.10
Package: update-manager 1:0.174.3
ProcVersionSignature: Ubuntu 3.5.0-18.29-generic 3.5.7
Uname: Linux 3.5.0-18-generic x86_64
ApportVersion: 2.6.1-0ubuntu6
Architecture: amd64
Date: Sun Dec 2 22:48:09 2012
EcryptfsInUse: Yes
GsettingsChanges:
 b'com.ubuntu.update-manager' b'first-run' b'false'
 b'com.ubuntu.update-manager' b'launch-time' b'1354468151'
 b'com.ubuntu.update-manager' b'show-details' b'true'
 b'com.ubuntu.update-manager' b'window-height' b'744'
 b'com.ubuntu.update-manager' b'window-width' b'1317'
InstallationDate: Installed on 2012-10-24 (39 days ago)
InstallationMedia: Ubuntu 12.10 "Quantal Quetzal" - Release amd64 (20121017.5)
MarkForUpload: True
PackageArchitecture: all
SourcePackage: update-manager
UpgradeStatus: No upgrade log present (probably fresh install)

[Robert Roth (evfool)]

Reassigning to aptdaemon, the package providing the download progress widget.

[Sebastian Heinlein (glatzor)]

Do you see this miscalculations often? Can you reproduce them?

[Launchpad Janitor (janitor)]

[Expired for aptdaemon (Ubuntu) because there has been no activity for 60 days.]

[Gao Shichao (xgdgsc)]

I 'm seeing this in 13.10.
What I see is mainly when downloading a package, for example deadbeef from a ppa. The completion ratio will change from 79% to 81% and suddenly back to 79%, together with the Downloaded size (in kb) change.