I'll speculate...I've purchased rock this way once (but not in this quantity!) The wholesaler/importer has their distribution point in LA. The rock comes in from Fiji, gets shuffled around for a few hours and then gets put on a plane to Denver without ever coming out of the box.
If the guy bought 400 pounds on sale it will probably cost him $1600 - $2000, depending upon who he actually bought it from. If he sells half for $600 he's better off than if he has to receive it all without any help.