beyond the other explanations that some have given, lego direct order releases ship from more than one warehouse, even in the US - my bricklink western train se

beyond the other explanations that some have given, lego direct order releases ship from more than one warehouse, even in the US - my bricklink western train set shipped from Vegas, and others I had chatted with either got them 3-4 days earlier than me or 3-4 days later, depending on how close they were to the warehouse and the order of the orders going out. just logistics, or luck as some of us call it?