I just read the opposite opinion, namely that sending small items in big boxes means that the companies are sending a parcel that mainly consists of air, that the bigger than necessary boxes fill up the vans transporting them faster than boxes of graduated sizes would and the delivery points' shelves as well.
These factors make delivery time longer, affect the environment, as not all packaging is recycled and more fuel s used for transporting the goods than would be needed if goods were packed in boxes that suited the amount of items.
There would be no point in my providing my source as it was the Danish Co-op's magazine for customers and therefore in Danish.