Just wondering if there is suppose to be different costs for different factions when upgrading identical items?

Example: I usually play Pariden and to upgrade the starting militia to wear a padded vest costs 27g to upgrade an Altar starting militia is 42g.

I can't see the reason why it costs more for Altar, neither faction seem to have any tech or starting ability that would change the price of armour or upgrading.

I didn't go too in-depth but I checked Umber, they only charge 27g too. I checked full upgrade from starting militia to endgame tech and the price was the same for each 18c/18m/210g so I guess it's just the padded vest but there may be more.

btw the Altar tech for Athican Leather shows in the tech tree and the sovereign select screen that it gives +7 defence, the item itself has +3 defence