Lead times explained
Lead time is the amount of time that elapses from the start of a process to its completion. In our case the process is preparing and delivering the order and it begins when the order status changes from "open" to "picking in progress", which is often referred to as locking the order.
The overnight process that locks orders uses lead times along with the order delivery date to decide when an order should be locked.
An order will be locked if the delivery date, less the dispatch lead time, less the preparation lead time is equal to today's date, or if the delivery date, less the dispatch lead time, less the longest product lead time is equal to today's date.
Setting lead times in your store
Preparation and dispatch lead times are set in the delivery slots. When an individual product needs more time than you have set in your delivery slots then you can make any order that contains it lock earlier by setting a longer lead time in the product. Products that don't need additional preparation time can have their lead time safely set to zero.