FOB Shipping Point (or Origin): Responsibility transfers to the buyer as soon as the goods leave the seller's premises. You book it when it leaves your loading dock.
FOB Destination: The seller retains risk and costs until the goods reach the buyer’s location.
The sale doesn't happen until the asset transfer occurs. Before that any cash you get from the sale is balanced by the liability to actually produce the good or refund the money. Or more likely you don't get any cash but can't record the bill as accounts receivable. It's not receivable until the transfer point is crossed.