I can't remember the last time I didn't go water->salt->culture->flour. It's not like I let the culture sit in the yeast water for a long time. It's probably less than a minute before I start mixing in flour.
Can you do me a favour and try doing the way I said for a trial batch next time you do it? I would love to know if you see any tangible differences in the process. Hard to imagine yours getting any better, but the prospect is tantalising.
For reference it was
Water >> Salt >> 1/3 of flour >>> culture >>> slowly mix in 2/3.
Of of curiosity did you ever use fresh yeast before Ischia? Only reason I ask is because its hard to get a reference point to how much to use, so I used the VPNA recipe I got from a restaurant and modified it based on your table to end up with
625ml Water (Bottled, ambient (coldish) temp) - I will used refrigerated bottled water next time
1.5-2grams fresh yeast.
Rest is your timeline. They are currently in the cellar
1 batch 5 Stagione, 1 batch Caputo Pizzeria.
In any case my Ischia should be here in the next couple of days so hopefully that batch is the last of the mohicans