NHF – new heroes for Heroes V 3.1.

To prevent the value 1 from appearing, you simply need to subtract 1 from the random number.
With a value of 16 in the current implementation, there will be 15 smaller numbers in the range [1; 15]. The probability is 15%.
But with a difference of 2 in stats, 32 will have 31 numbers ([1; 31]). The probability is 31% instead of 30%.
With a difference of 6, 96 will have 95 numbers, meaning the probability is 95% instead of 90%.

In the end, we get a probability that is not difference*15%, but difference*16%-1%. If we simply change 0.15 to 15, the probability will become difference*15%-1%.