I think our respective positions are clear on this: you argue from a statistical point of view, I argue from political realities, knowing how the Norwegian three-party (employers, unions, government) labour negotiation system is built up and works. When workers legally can strike at one and only one time of the year, that's when they will strike, independently of any external factors.
Your statistical theory might be correct, and if it were, I would certainly love to see the negotiations moved to November, missing out of the recurring strikes every May.
But I do not think we will agree on this topic, so I suggest that we leave it there.
November or February would be good, but I'd even settle for elimination of 75-80% of the May red days/holidays.
The political reality is that there have also been disruptive labor actions, legal or not, in January in Norway too. Just usually not as intensive and extensive and regular as in May and June.