TDO is simply the product of DPS (how much damage a Pokemon deals per second, on average) and how much time the Pokemon lasts in battle. Calculate TDO (total damage output) for each Fast Move and select the best option.Dragonite with Dragon Claw or Magneton with Discharge).
This method for selecting a Secondary Charged Move was chosen because the battle algorithm prioritizes fast Charged Moves over the Main Charged Move in certain scenarios, so this helps give Pokemon access to their faster attacks even if they aren't as efficient on paper as other options (e.g. Since this weighs moves by energy, fast-charging moves are more likely to be selected than slow ones.