Just want to note a few things that came to mind when reading this update.
* The "number" (as in not a zero) as a result when asking about him casting dirtamancy to put out the fire reminded me of this update
. Parson doesn't have the "Dirtamancer special" but could still cast Dirtamancy at terrible odds. Is this conclusive that he is a Caster? Not sure, but everything so far points to it (not only here but all throughout the story). What I think it's safe to assume is that he has the ability to cast, even without a scroll to read from.
* Maybe it was a typo and I'm reading too much into this, but another thing that caught my eye is the following:
“Odds of me casting this spell!” he shouted at the bracer.
The same number as before flashed, then changed to: 0.0
If the odds of him casting the spell (without specific target) are the same number as the odds of him casting it on himself, why would the bracer ask to specify a target in the first place? If the spell is designed to only be casted on Parson (as Jojo intended to), the bracer shouldn't be asking. And if the spell can be casted on some other target I would have expected the numbers would be different between specifying and not specifying the target upon which he intends to cast. Specially if Fate was involved in the 0.0 results as many (including myself) believe.
* The way the bracer worked
The window showed a long decimal number, then blinked and showed a short one instead. Then it ran through a series of digits that changed every split second. Then it went blank.
reminded me of a computer doing calculations on an iterative process until it reaches the final result. If that is the case, as many people are saying, it wouldn't be too far-fetched that the first number is the result of the iterations until the bracer includes Fate into the equation (which would be the last step of the iterations) and that is why it switches from 98% to 0.0.
Also strange about this is that even though Parson doesn't seem to be a Dirtamancer, he has the odd chance (about 1 in a million) of casting Dirtamancy to put out the fire, yet he has 0.0 chance of casting that scroll. So I would expect that implies that the problem here is not the inability of Parson to cast the scroll, but that there is a 100% chance that someone or something will stop him if he tries to cast it.
One other thing about what I've read from people saying the bracer or Pasron's perception has been tampered, if we go by what we know form Stupid World maths there are equations that can give more than one answer so maybe the "equation that models the scenario Parson is asking about" looks something similar to our quadratic equations and in this case Fate (or however you may want to call it) is the reason why both those results are given. If Parson "beats Fate" he gets 98% chance, if he doesn't "beat Fate" he gets 0% chance. And for whatever reason the bracer is not "sophisticated enough" to predict if Parson will "beat Fate" right now or not.
* One other thing that went through my mind with this update relates with Charlie's intent in spending a calculation for this. Reminded me of this
Charlie knows that those calculations are valuable and that Parson can gain from performing them for Charlie. So why would Charlie spend a calculation to teach Parson that he can cast?
He couldn't do it "for free" or Parson wouldn't believe it. And it seems Charlie gains nothing from Parson learning he can cast. Quite on the contrary it looks like something Charlie wouldn't want to hint Parson on. So why spend a calculation on that?
My tin foil here is that there is a pretty heavy plot between Charlie and Fate and Parson is the Wild Card in it.
First of all, Charlie (together with Haffaton) arranged for a Summon Perfect Warlord spell to defeat the sisters and get the Arkendish. After that he got some predictamancy telling him that a Stupidworlder would destroy him and he thought he had fulfilled that prediction with Judy. When another Stupidworlder came in he was not thinking on that prediction, but when Parson survived the battle for Gobwin Knob the way he did, Charlie started paying more attention and got more Predictamancy casted on Parson. He learned that Parson will be the one who takes Charlie down, but also the one who will eventually "breaks/beats Fate". So Charlie is pushing for Parson to "rebel against Fate" before he gets to destroying Charlie hoping that Parson breaking Fate will nullify the other prediction (Charlie is trying to go with the "very easy way" but will end up getting the "very hard way").
What Charlie is trying to do with spending this calculation is to get Parson to acknowledge how much "Fate" is controlling his actions and his free will so Parson focuses on "destroying Fate" instead of "destroying Charlie".
So "Fate" is trying to get Parson to destroy Charlie (mainly through the GMTTA) and Charlie is trying to "rig the game" and get Parson to destroy "Fate".
Parson will finally realize this at the end of Book 2 and since he consideres himself a "player" and not a "piece" that these "two GMs are manipulating", Book 3 will be him going against both Charlie and "Fate" and destroy both