Example Display to Customer

Here are some example displays using same products in cart, affected by configuration. 

Multiple Warehouses in Cart – Shipping Estimator 

Below shows items from multiple warehouses in the cart – but 1 set of merged rates. 

Multiple Warehouses in Cart – Shipping Estimator

This is same as above but here both warehouses support UPS, so a UPS set of merged rates is shown. 

Single Warehouse – One Page Checkout

As can be seen checkout is done using standard one page checkout functionality when just 1 warehouse is in the cart.