Hi Caimie,
Actually it's less than that, no?
i180 Main Hand:
* Craftsmanship: 278
* Control: 149
* CP: 0
i170 Main Hand: (Base Stats, No Materia Yet)
* Craftsmanship: 263
* Control: 141
So the i180 is initially ahead of the Crafted i170 by: +15 Craftsmanship, +8 Control.
To make up for that difference you HAVE blow 4 Slots (out of 5) on the i170 just to catch up and exceed that, with the 5th Slot being CP. So:
* Craftsmanship Tier V: +11
* Craftsmanship Tier V: +11
* Control Tier V: +7
* Control Tier V: +7
* CP Tier IV: +4 CP
That brings you up to: Craftsmanship 285, Control 155, CP 4.
So you only *gain* +7 Craftsmanship, +6 Control, and +4 CP compared to the i180.
That's paltry for blowing Millions and Millions on Tier V Forbidden Melding IMHO.
