Does anyone know how to level up an homunculus?

[P 15-4704]

I tried killing enemies in the range of the homunculus level, and also tried my level range, but it barely get exp (less than 0.1% per mob).Im using some exp boosting equip (costume googles, happy balloon and saehrimnir gloves). My Homu is lvl 42 and i'm an alche lvl 99.
In the warp portal forum i only found a leveling guide from 2012, and i'm sure things changed.
Is that normal?