The Blacksmith Hammer Black Dragon Touched Hammer, Item ID 191228 has a bonus "When inspired, increases the Skill provided to Dragon Isles crafts by 15%.".
This bonus is not taken into any calculations, as also shown in Simulation Mode

Seems to have changed with 10.0.5
fixed with 5.5.6+

Pretty sure it didn't before 10.0.5 either, because it has been on my mind for a months time by now.
Perhaps due to my hammer being R4?