Adding items to an already approved Purchase Order

[Jonathon -- Improov]

Adding items to an already approved Purchase Order seems to leave the newly added items at status 
of "created", with no way of changing the status to "approved".

Does the fact that the status is not at "approved" affect the shipping? I tried to receive the 
shipment, and I got only the approved items, not the non-approved (newly added) ones. How are 
shipments tied to POs?

Also, is it actually possible to receive the same PO more than once? Why? Receiving the PO more 
than once didn't give me more inventory, though, so it's not exactly broken here.

Why do I get multiple items for the same inventory (say I get 2 items for Product ID Cap)? I get 
this by doing the above PO, where 1 Cap was in the original PO, and the 2nd Cap was added later, 
all before the inventory receive.

In general, the entire SO/PO and shipping and inventory receive seems very buggy, or at least 
missing several necessary constraints. Any documentation for these areas? Or are they "work in 
progress"?

Compared to the Product Configurator (still buggy since it doesn't refresh storefront in timely 
fashion) and the Variants mechanism (looks perfect), the above areas seem very unfinished.

By the way, some time back, I had also somewhat documented the inventory area with respect to the 
order fulfillment and stock inadequacy aspects. There are certainly at least (or exactly?) 2 items 
for each inventory: 1 for existing stock, another for backorders. Is this better documented anywhere?

Jonathon