I don't know enough about the orbats in ToD, to say much definitively, but I had taken a look at the Long Tan scenario, and noted that the game map is fairly large for the average 12 turn SB scenario.
It also got me thinking that I need to learn more about that battle; mind you I had soem help from Tallin here... about maybe working within that title to see what I might be able to come up with.
I eventually got hold of some 1:50,000 scale maps of the area that I think according the the USGC site said were made during the Vietnam War period. So who knows, but I suppose this is sort of the start of an entire process.
For me, it isn't so much a question of "are the orbats wrong?", but rather, do I have access to modify them?
Then too maybe, if I get hold of a fan of the series, and see if I can get the map expanded (or modified a bit) if needed.
I think this map has some buildings on it that are not present on the game map.
Mind you both of those are zoomed out a fair bit - so it isn't actually an accurate image of the level of detail I found. I think that the game map might have enough room ( I created a larger stitch shot of the actual map to get an idea for about how far any relief forces would have to come ).