That doesn't seem to be the case either. That would be a fixed roll where it would only depend on your stats and not the NPCs.
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This is a roll I made and if that was the case it would mean I had -59 manipulation which isn't the case.
Less dice roll is
better.
That's probably what brings most of the confusion.
So there's a probability of success. It is itself based on relevant factors (most notably your relevant skill, obviously - but possibly others too).
Then goes dice roll between 1-100. Think of it as a
negative modifier to the said probability. Therefore, the less the "malus" - the better.
It's actually very convenient, since you can right away estimate the probability of success by straight up adding together the
Dice value and
Result value.
Take a look at this. It's the same exact action roll, made by reloading the save.
Following what I said, add it up:
1) 80 - 25 = 55
2) 75 - 20 = 55
3) 2 + 53 = 55
Meaning, it's 55% chance of success for me, based on my Charisma skill (and hell knows what else, if anything).
Rolls
above 55 will fail and vice versa.
There's also a critical success on 1 - as I understand, you are always successful if you happen to roll 1. So you seem to always have that 1% probability, no matter what.
Sometimes it's impossible to fail, then this will look like this:
Even though the roll is 95, as you can see I'm so loaded here that the dice has no bussiness whatsoever, no matter what is it.
Conversely, in your case, it seems it's essentially impossible to succeed (
negative 59% chance) and you should not waste time and think of a different approach.
Take note that, apparently, some rolls may work differently - specific example would be a training roll. There, the more is the better (at least the last time I checked). If there are many of such instances and where - I've no idea, never bothered to place a ruler to it. The point is that there's at least one such case, but generally I think it works as above.