Uhh,, if you read the policy closely and from talking with them in the past they will NOT hold an item such as a flat of primers for you while waiting for your powder to come back in stock. If the primers you want are in stock but you opt to wait for your whole order they will sell the primers to the next customer. When your powder comes back in stock and then all the primers are gone too bad. Now you wait for primers and run the risk of them selling all of the powder you need.
This make sense. In my case my powder is in stock, however the primers I want is out of stock. When PV gets the primers they looks to see if my powder is in stock, if it is, they ship everything at once. That's the way I understand it. They will not ship my powder unless I tell them I want it right away. In my case if I wait for primers, by the time they get the primers, my powder my no longer be in stock