this might be good to know

the other day i picked up a flawless elemental battle-stone, and chose to use it on my teldrassil sproutling, an uncommon pet i had already leveled to 25. doing this knocked her back down to level 23 - the same penalty you take when you capture a wildling. however, this did not negatively affect my progress towards pro pet mob. today i leveled her back up to 25, and this did count toward the achievement.  just fyi.