Gratz on hitting lvl 50... now felt the pain of mission 7 farming

(and i mean the higher sparkle recipe)
Regarding the blacksmith employee.
1 of the info in himeuta mention this:
Estimated Crafting Rates:
+1: ~11%
+2: ~4%
+3: ~0.001%
So does that mean the employee for crafting is mostly only for the bonus ? (cuz i do actualy get the 2-3 bonus alot nowday with puting my team in there *dex raging 150 / 2x archer on 250 dex 200 dex*
Btw the +3 i don't believe its that low since i got 2 x +3 gear although they are low lvl equipment...
If it is that low, how come i never got black unit in aigis base / sp gacha >.< they are about the same rate