First of all, we have taken time to check the code to ensure that everything is fine. After our check, we found out that everything was fine and no updates were issued.
Now that you know that we actually investigated, I will share the full story for future reference.
The game uses chances in quite many areas. Chances are used to imitate real conditions. We want to simulate the game as near as we can to real conditions. This is why most chances given in the game, unless stated otherwise, are all simulated.
What simulated means?
It means that every time, the game will roll a dice to decide on what will happen.
What chances mean?
Chances are our effort, as a development team, to push the simulation towards an expected event.
How stable results are?
Haron and Nelson said it all. First of all, it is down to luck. If you have terrible luck, nothing will work. If you have great luck, all will work. However, the more results you try/examine, the closer you will get to the chance given.
An example
The best way to test, are the Flip a Coin cards; everyone has a coin so you can test it right now, without using your cards. Flip a coin cards have 50% chance of success. You may cast 5 and get them all failed or all successful. Both results are acceptable and probable to happen. As a player, you will tend to observe the failed part - its normal.
If you try 100 casts though, the results should be in between 40-60 span (difference of 20 at most). 1-99 is impossible, 30-70 is pretty rare, 40-60 will be the most common result.
75% is pretty aggressive and every % added makes it even more aggressive (it matters most). That's something you can realize in your own by using a dice (a d100 one, this is the one we most commonly use). The way I realize it, the difference between 25% to 50% and 50% to 75% is not the same. Even if mathematically speaking, it is.
Battles
Battles produce more solid results due to improved design. The dice used there is better too.
Voodoo
Voodoo tend to produce less solid results mostly due to the lack of any rules interference. There are no caster and victim traits/rules that interfere. If there was, the results would be more driven and as a result more expected. This is something we can always improve in the future.
I will move this topic to general discussion and futurely, I might make a guide out of it.