Lower level dungeons are a bit more inconsistent about how much you can pull, a combination of the tank's weaker defensive kit and the dungeon not adhering to the incredibly stale "2 trash packs -> wall -> 2 trash packs -> boss" design, meaning you can actually potentially "pull too much".
If you are however still single pulling after level 70 then what even is your purpose in that party? You could be replaced by an extra DPS and the run would not only go the same, it would most likely be faster...and give the healer something to do for once besides wearing out their AoE damage hotkey.