Nooooooo, that's not how they work. If you pre-order something with a current item, the current item is held until the full order can be shipped. This happened with the Padme maquette I ordered for Jim and our holo-sidious figures. We got the Sidious figs about 2-3 months after everyone else. It also happened to me last spring, I think with the adventure Kermit's. I had to write to them to ask them to ship separately.
In one respect, it's a good idea to help keep the shipping costs down, so I believe the action is borne out of trying to not over charge on shipping and piss a customer off.
I learned (most of the time) to not preorder with current items on the same order. I actually deleted the bust ups stormies once so my Vader chrome bust would be shipped sooner.