I edited my Pokemon save file and added 6 level 5 pokemon. On Pokesav there seems to be two options, to edit the pokemon level 1) by selecting the "stats edit", and 2) typing in the "Lv" and under "secret Id" but above "EXP". I have input both values 5 for all the pokemon in my party, and all six pokemon do not level past 5. They still gain Exp, but no stats boost or visual change to the Lv when the exp bar fills. Thanks for reading!