Well, krinid, I agree with you on most parts, but functor's original post actually got deleted by now, so what does that tell us?

Well I wasn't able to read it so I dunno ... haha

I don't fully understand what it means to be deleted or downvoted tbh. Did multiple people downvote it so it dropped off? Or did Fizz delete is?

Well, phase4 information that are correctly available is only their unlocking cost and value, since people have reach it. But so far nobody (as we aware of) have do the unlocking to get the additional info about the incremental cost and value. If some people get those information by 'other means' (which Fizzer referred as reverse engineer) than they are not allowed to be shared. It is technically illegal to do reverse engineer.

functor's post was about the AP costs for the first upgrade (not unlock) and every upgrade thereafter. I don't know how he got them and honestly, I don't care. Perhaps he is friends with some player who has maxed out every single advancement but doesn't speak about their achievements publicly (perhaps because of language difficulties) but told functor. Perhaps he analyzed the app's resource files (which, to be honest, to me is almost like public knowledge, android apps adhere to a standardized format and no-one can prevent me from simply extracting an archive file, if something should be kept secret, at least encrypt it). What I know is, that I haven't saved his post locally in order to have them now that they were deleted. Mostly, because by the time I've finally reached phase 4 this information will already be public. And for everyone like me who is months (if not years) away from reaching phase 4, why would I care about those numbers at the moment. We already know the advancements that phase 4 brings and if players are determined to upgrade some advancement, they will do so (almost) no matter the costs. I enjoyed playing WZI even before I found out about all those spreadsheets players were linking in the forum.

For any #'s which aren't confirmed by someone unlocking them, we simply base the math on what has come so far. We know the mechanics for AP Adv (unlock cost + incremental cost) & artifacts (value of each upgrade level doubles).

Are there exceptions? Yes, like Speedy Crafters is <2x the previous level (which is sad tbh, it's a broken system when you have to invest in something before you even know how much value it will give you - just show the target up front; same with AP Adv, show the incremental values; no one likes bad surprises).

We'll correct these incorrect assumed values as we learn verified information. People are tracking all of this in Google spreadsheets and sharing among the community.