I had my aux belt changed at Angelworks a couple of weeks ago and I can safely say that it did not take more than 2 hours and that was inclusive of some time spent struggling to remove a tool from the side of the engine before lowering it back in.
We charge 3 hours which includes the 36000 mile service, its not that hard a job if you have done hundreds, official book time is 2.2 hours.
Bumper does not need to be removed either to do them.