The upgrade rates seem a lot higher than upgrading regular equipement. With 15 Pieces of Shadow Gear Equipment I was able to make the following with regular Elunium and Oridecon.
+7 Shadow Weapon
+4 Shadow Armor
+4 Shadow Shield
+6 Shadow Shoes
+8 Shadow Earing
+4 Shadow Pendant
4x Shadow Weapon
1x Shadow Armor
1x Shadow Shield
3x Shadow Shoes
5x Shadow Earing
1x Shadow Pendant
I think gms screwed up and switched the elu and enrich elu options, I did all my unsafe upgrades with enrich and it all broke after +5 and I had more items than you.