Artisan Archive

I have just recently decided to go up the engineering ladder so that I could build myself some harvesters, and I thought that should yield some good xp which would be good to help max out business as well, only to find that crafting harvesters doesnt give general crafting xp but instead gives structral crafting xp. What is the deal?? Making one is an artisan skill so should give general crafting xp. When I make a starshine surprize I don't get food crafting xp and it should be the same with harvestors.