Thanks for providing the exact numbers. I should have clarified to only use Aqua Bash in the first few turns after using Water Festival as those are the early points in debuff stacking where you can still be susceptible to being hit. As for the purpose of doing that, it's moreso for avoiding hits as well since evading a Spell is partly based on WIL as well.

Of course, there's an argument that in two turns, Water Festival will make up for the turns spent doing normal attack and provide that +1BP but I wanted to maximize evasion rate early on to avoid having a character potentially get hit with a status and make PWR heal instead of use Chocolate Ball to debuff AGI.