I would really be surprised if that tower notch has been passed by "engineering" in Australia. The suspension stuff has, but I assume you could not get a notch plate kit like that passed as "engineering" would depend on the weld quality of the installer.
That being said, there is no benefit to that strip up the middle, quite the contrary, it "could" provide a fracture point if not welded correctly. It also does nothing to reinforce the lower arm inner mounting point as the standard tower does.
All this is "mute" in your case as the fabrication is to a very high standard. But as you would know, when selling this stuff you have to build it for the lowest common denominator, that being the USA.
The first big lawsuit from the the US, when it happens, will be interesting.