I am currently testing/practicing breeding for IVs, and I could really use some help.

This is what I got so far:

Parent 1: Jolly Magikarp @ Everstone with the following perfect IVs: HP/Atk/Spdef.
Parent 2: Ditto @ Destiny Knot with the following perfect IVs: Speed/Def

Is this correct? The offspring I got only had Def as it's perfect IV.

I'm fucking confused