I wonder why similar skills cant provide us with a lower chance of a skill lvl up.. U need a card with with exact the same skill to get a 15% chance, but I've been wondering why a similar skill of a lower lvl cant give for example a 7.5% chance per card... Or similar skills from different element give a lowered chance at a skill level up as well. Let me give two examples:
1-a Cerberus' "does heavy fire damage to a single enemy" gives a 5% chance at lvling up a Gigas the Saboteur's skill "does heavy earth damage...
2-A medusa's skill gives half the chance (7,5%) at lvling up a Medusa the Jealous' skill..
There are various skills which are so obviously similar I think its very strange they give a zero percent chance at lvling up another card's skill. Even a vampire queen's skill gives 0% chance at lvling up a vampire skill!?