Regarding the enhance attribute:
When maxed, it doesn’t give a 60% bonus. It gives 50% instead.
At level 1, with full attribute, it is supposed to give 914%*1,6= 1462% SFR (or 1463% if rounded up)
It gives 1371% SFR instead (that is, 914%*1,5).
Regarding the arts enhance attribute:
It does nothing. At all. I have put 3 points on it and it still had 1371% SFR.