The additional security was not requested for the consulate facilities in Benghazi. They were requested for the Embassy facility in Tripoli. Extended security was requested this summer by Ambassador Stevens for the facility in Benghazi, maintaining a minimum of 3 security agents. At the time of the attack, there were 5 security agents on duty, more than had been requested for that facility. The two additional were escorts for the ambassador.

What you’ve said makes sense about the mortars. The reports I’ve seen haven’t mentioned mortars, or at least if they did, I missed it.

I’m still more than a bit confused about why whether it was planned or spontaneous is important. Either can fit the definition of a terrorist attack, if that label is preferred. And Obama acknowledged it as such. (The significance of that also escapes me.)