The 3 PDR is strange. First, it appears as a reinforcement in Berbera if the Hobart is placed there. But the Hobart can simply setup in Berbera and then move out. I don't see the need for rule 13.3.
The only use for the 3 PDR is to negate the armor bonus. And the only armor is in De Simone column. Can it be used? The armor cannot be used in mountains so the Argan Pass bunkers don't need an AT. Barcasan could use it.
The 3 PDR has foot movement of 2. If it starts setup in Berbera it can reach Barcasan in Turn 4, just in time to face De Simone. If it goes in another direction or starts in Berbera later the Italians will reach Barcasan before it.
So it's use seems pretty straightforward. I think two or three rules could be spared and simply place the AT in Barcasan at setup.