I took a look at the calcs and found that the given defensive spread does not guarantee surviving Z-Hydro Pump and Scald from double ducks; changing the spread to 244/188 guarantees survival with at least 1 HP:
252+ SpA Pelipper Scald vs. 244 HP / 188+ SpD Eviolite Porygon2 in Rain: 49-58 (25.6...