I am currently in the progress of leveling my third Iron starlette and Ive made some curious observations. Not once did a lowbie seem to miss against a higher level pet, even if it only did trivial damage.
Right now I am in Vale of Eternal Blossoms, leveling it on Wild Pets as Ive exhausted all the trainers today, and my lvl 20 Iron Starlette is rolling over the lvl 24/25 mobs with impunity. Not seen a single miss yet.
Only times Ive missed is when theres been a hit debuff, such as stench, slippery ice or sandstorm.