We’ve just added ALLPCB to our Fabrication price comparison list. ALLPCB is an unusual company: when you do a search for prices on their site, it returns the results from several different Chinese factories. You can then choose which factory to order from, although ALLPCB still handles the ordering process.
When PCBShopper shows you a price from ALLPCB, it will be from the factory offering the lowest price that meets your schedule (as specified in PCBShopper’s “Boards arrive in…” field).