I think we might be saying the same thing.

>>1.2 charges on a guy gives 20% chance of 2 charges and 80%
>>chance of one.
>>
>>Therefore if you killed 5 such people you would expect to
>have
>>6 charges. However, you might only have 5 or you could have
>>as many as 10 (which would be very unlikely).
>
>Why would 1.2 charges give you 80% chance of 1?
>
>1.2 would give you 1, and 20% chance of 2.
>

If you have a 20% chance of getting two charges (which I think we are both saying), and the only other possibility is getting one charge (which I think we are both saying), then the odds of getting one charge must be 80% (100% - 20%).

20% prob of 2 charges, coupled with
80% prob of 1 charge
===========================
100% prob of either 1 or two charges

>Thus the drunk spake, and then was sworded!