I had thought that shipments were set up to be based dynamically on some metric like player level and need, but of course that would be too sophisticated. What we instead get is another Skinner box where players are getting conditioned and reinforced to jump at the "valuable", "rare", "required" or "necessary" reward.
But alas the notes mislead me:
Shipments
We have improved the Shipments feature to allow us to sell items that are more relevant to the player, such as high value gear.
Refresh times will now refresh at pre-set times each day (instead of 6 hours since the last refresh).
The pricing of materials in Shipments have been retuned.
Shipments now support a wider variety of items to be sold.
Ability Material III is now available in Arena Shipments.
An additional slot has been added for Shipments.
Gugek
