Why just an ANZAC OOB?

[TDR]

Andy, true is been there since SPI, but fundamentally why?

True we as two distinct nations sometimes join under one HQ but we do not live in the same tent for every war, WWII is an example.

Don, I was not complaining, just asking why this adherence was still being carried on.

I do not see ANZAC in MBT yet we were in the same places, Korea and Vietnam for starters, though New Zealand is not listed in MBT either.
You made the split for MBT, so was there a reason to keep the status quo?