I just noticed your recipe says 300-400ml of water. Why such a large variance? I went to the calculator website and they tell me 312-469 ml of water. That's a huge difference I would think.
It appears as a big variance but once you start making soap the amount of water will seem negligible.
Less water= a harder bar sooner, but I shoot for somewhere in the middle and let my soap cure and finish saponifying. My observation is that the more water one uses a better reaction one gets and while less water allows for a firmer bar sooner, the soap is more harsh initially. Still needs to cure for a few more weeks.