The Warband Valorstone Discount is not working when it comes to upgrading armor across your Warband.
The way this discount is supposed to work is that once a player receives a certain item level in an armor slot, any other Warband character can upgrade to that item level with a discount on their Valorstone costs.
Example of Valorstone Discount in the Ring slot
Currently, players are not receiving this discount on their other Warband characters. When players hover their cursor over the total costs to upgrade, the Valorstones Discount window does not pop up and players are still charged at full price to upgrade their gear.
In personal testing, we used two rings at 603 and 610 item level respectively as a reference. When trying to upgrade another ring on a different Warband character, we did not receive a discount on the Valorstone costs to upgrade that ring up to 603.
Reference character (left) and costs to upgrade a ring up to 603 on a different Warband character (right)