Raise skills defense seem to be not working or the increment to it is so little that make it useless.
Tested on different generals and with different amount of lead seem to have no affect.
Added as much as 70 level of skills, end result is as tho nothing was added.
Please look into the matter and adjust skills. To have wasted golds to refine a 4 star gear and get a useless skills is very discouraging.