Without sc hammers it's 13.09 gp/xp doing addy plates.
88-99 is 8,648,655 xp
8,648,655 * 13.09 = 113,210,893
With sc, this cost is halved. -> 56,605,447.
1 sc hammer used on smithing will give approx 64k xp.
For 8,648,655 xp, you'd need about 135 hammers or 2,700 sc points.