Do not Separate pre-orders

The Preorder app is creating separate orders when a customer purchases multiple items—one in stock and one on pre-order. This results in a shipping cost increase after checkout. Specific Case: For order BBQING#56954, the customer initially saw a shipping charge of $49.95 at checkout but was ultimately charged $69.90. The shipping method description for this order shows: Shipping (81.0 lb: Items 56.0 lb, Package 25.0 lb) This does not align with the expected setup, which should reflect: Parcel Surcharge on orders between $0 and $999.