ubers are not classified with levels, but rather the actual pokemon itself.
competitive pokemon battling has been divided into tiers and the most common battles are fought between the same tier. this is done so that stronger pokemon are not used against weaker pokemon, which would make the battle relatively unfair.
tiers are divided into the following: ubers, OU, BL, UU, NU, monocolour, etc... with ubers being the highest in rank. the pokemon in the uber tiers are lets say 'banned' because he have certain features (ability, stats, etc..) that makes the pokemon unfairly overpowering in battle. if you need to know more, just look it up yourself
also i would like a battle :D FC in sig
mixed tiers, no ubers, 6v6 5th gen only. thank you