Island Sanctuary supply dramatically shifting in the background

[Rowde]

I'm not at the place where i'm ready to hard test stuff myself

and considering that i'm well behind other ppl on the content the answers will probably already be out there if and when I decide to look stuff up

So far here are my observations across my 8 characters

Supply has a "default" value that it changes to each week for all characters at weekly reset
Supply changes independently on each character during the week based on what they craft during the week so by the end of the week they can each have different Supply stats for items
The Supply I end at each week has no bearing on what Supply changes to at next weeks weekly reset
I could be overflowing on an item I crafted a bunch of at the end of the week and at reset it shifts down to Sufficient
I also observed items with nonexistent supplies shift up to Sufficient despite me crafting zero of that item during the prior week

Predicted Demand is a hard indicator of next week's Popularity
It just slides over and replaces popularity and each character has the exact same changes to Popularity each week regardless of ending Supply


So the big question then is what does the Demand Shift field actually tell us?
Since it doesn't seem to actually have any bearing on Predicted Demand my current working theory is it is telling us 'How many of an item we can craft before the current Supply of that item changes in the current week'

I don't have hard numbers obviously but I imagine if something has "Plummeting" Demand Shift then each craft would increase the current Supply for the week regardless of Popularity since "the item isn't being purchased as much since demand is down"

So say if you have an item with Very High Popularity and a starting Supply of Insufficient but Demand Shift is Plummetting
my current theory is that each craft of that item would tick up Supply by 1 so within 3 crafts of that item it'd become Overflowing supply which kills the value of that item for the week
so with that example if I wanted to make some decent profit from that item I wouldn't want to craft it more than twice during that week and ideally after Groove was higher


but like I said that's my current working theory based on my own observations and I wouldn't be surprised if there are hard answers out there already with enough searching

[DarkCobalt]

So the big question then is what does the Demand Shift field actually tell us?
Since it doesn't seem to actually have any bearing on Predicted Demand my current working theory is it is telling us 'How many of an item we can craft before the current Supply of that item changes in the current week'

From what I can gather from other posts and guides, it only tells us how much the item has shifted in the past day, which means it's just telling us how it moved compared to yesterday. Not very helpful in that regard lol, as it's just telling us what we already know, especially because 2 data points =/= a trend (as my statistics professor likes to say, and is clearly evident from the behavior of the items today where they shot in the opposite direction). I think it's probably just that the demand shift is based on what other people are crafting, but we have no UI telling us any of that so it's only a guess.