It's been a while since I last saw that "finish updating" screen after rebooting during a program update from within the UI (win 7 x64 system), so I have to agree that the OP's not entirely off-base. However, since I'm not getting Chrome installed either, my personal guess is that the Avast crew is finally in the middle of changing that opt-out monstrosity to opt-in, and still has some cleaning up to do.
On a related issue, I haven't seen that express/custom installation choice in ages, and have to assume that it's only in the installer for a clean install.