Is the % that they tell you the ACTUAL %?
Or is it just a rough amount?
Or is it not that amount at all?
How can we ever verify?
I'll tell you why I ask this question.
I can say, without a doubt, whenever I have used 10% scrolls on something unneeded or a junk item, it has almost ALWAYS worked.
I can say, without a doubt, that I have used 16 50% scrolls on something good, like a unique item, and only 4 of them succeeded, which means that is a 20% success rate.
Of course, the more you scroll in a row, the more accurate the actual % would be, i.e. using 100 of 50% scrolls.
I know that Nexon gave out a reason as to why you shouldn't expect 50% scrolls to work exactly 50% of the time, and that is called "the gambling falacy". Where probability does not affect the genuine outcome. This means that even if you flip a coin 50 times, you will always have a 1/2 chance to have heads or tails, even if you flipped 49 heads prior to the last flip.
However, that is only slightly true. It's accurate to say, that flipping 49 heads/1 tail is equaling flipping 50 heads has the same statistical SEQUENCE outcome. But it is VERY false to say that flipping 50 heads in a row is more probable than something like 35 heads and 15 tails. This is the OVERALL outcome.
The gist of this means that even though flipping the following: heads, heads, heads, tails heads, heads, tails = heads, tails, heads, tails, heads, tails...
Does not mean it is equally likely to have an outcome of: heads, heads, heads, heads, heads, heads
Especially when getting into more consistent and large amounts of flips.
I also did a physical test, I flipped a coin 50 times - 27 heads, 23 tails. Pretty even, but I only did it once for now.
However, this also made me realize that IRL variables (such as how hard you flip, the consistency of how you flip, where the coin lands, etc) makes it so that it isn't a genuine 50/50 chance.
Which further puts me in a position to question whether or not these "% scrolls" reveal their true percentage.
In-game programming SHOULD allow for more precise/accurate/consistent chances since there are no outside variables that will effect the outcome of fail or success; heads/tails.
Yet, it is somehow less accurate, and less precise than probable theory/hypothesis and physical testing.