The two are in agreement for me.
I did an "apt-get update" less than a minute before and Update Manager is in screenshot.
coffeecat@amd4-testing:~$ sudo apt-get upgrade
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following packages have been kept back:
The following packages will be upgraded:
binutils firefox firefox-globalmenu firefox-gnome-support firefox-locale-en
initramfs-tools initramfs-tools-bin libaa1 libatasmart4 libcddb2 libcroco3
libmpg123-0:i386 liboil0.3 libsmbclient libtheora0 libvpx0 libwbclient0
libwbclient0:i386 libxp6:i386 libxpm4 polkit-kde-1 python-gobject
python-gobject-cairo python-pkg-resources samba samba-common
samba-common-bin smbclient thunderbird thunderbird-globalmenu
thunderbird-gnome-support wamerican wbritish
33 upgraded, 0 newly installed, 0 to remove and 1 not upgraded.
Need to get 74.7 MB of archives.
After this operation, 361 kB disk space will be freed.
Do you want to continue [Y/n]?