there is. I dont know the formula, but Ill post an example, maybe you can figuer it out yourself.
¤¤top Cgrade, Ghoul's Staff¤¤
Enchant Level # of crystal returned
If it fail from +3 to +4 1361 C crystals
If it fail from +4 to +5 1451 C crystals
If it fail from +5 to +6 1541 C crystals
If it fail from +6 to +7 1631 C crystals
If it fail from +7 to +8 1721 C crystals
If it fail from +8 to +9 1811 C crystals
If it fail from +9 to +10 1901 C crystals
If it fail from +10 to +11 1991 C crystals
If it fail from +11 to +12 2081 C crystals
If it fail from +12 to +13 2171 C crystals
If it fail from +13 to +14 2261 C crystals
If it fail from +14 to +15 2351 C crystals
If it fail from +15 to +16 2441 C crystals
If it fail from +16 to +17 2531 C crystals
If it fail from +17 to +18 2621 C crystals
If it fail from +18 to +19 2711 C crystals
If it fail from +19 to +20 2801 C crystals
If it fail from +20 to +21 2891 C crystals