Inaccurate Percentages

[Kakure]

I call this this the X-Com factor, if you have ever played X-Com Enemy unknown, you will know exactly what I mean.

X-COM uses random numbers just like any other game.

The game saves your seed, or maybe a sequence of random numbers pre-generated when you start a new game or load a new zone or whatever, to prevent you from cheating by reloading a saved game to get different combat results. That is intentional and in no way is it evidence that the numbers are anything less than random.