Wind Serpent resisting too much??

According to Cheeky's Spreadsheet, which is very accurate and well made, Lightning Breath from a Wind Serpent is supposed to average out to about 13% - https://gyazo.com/659cf94cbe8e94f1b614d13e182fb975 . When I did Magtheridon today, my pet's Lightning Breath resisted 22.7% ! That's almost 10% more than it should be - https://gyazo.com/a6e703f6ac961b49d72988573a87d652 . Should I report this as a bug or is there something about Magtheridon with increased Nature Resist or what's up maaannn?