In the past, I have used Rock Auto Parts for delivery in the US. They often say up front something like: We may ship from more than one source to speed your order. What they are saying is when you are ordering more than one part, that one warehouse may have one part and be out of stock---OOS-- on the other. Rather than hold your entire order up: 'backorder' , for that one OOS item, they will ship a partial order for that one item that they have in stock. The OOS item would then be shipped from another warehouse. That may be convenient for a parts customer in the continental US, but very expensive for those outside the US like Mike .308. I thought that they were giving you a choice at that point. IOW you can chose to wait and get the entire order from one warehouse. In Mike .308's case, he can chose to accept his order from only one source which would save him some big bucks on shipping overseas even though the order may take longer.

 

correction: In the above para., OOS should have been N.I.S. for Not In Stock.