Hey!
The best way I can describe this is similar to flipping a coin…
There’s a 50% chance that it lands heads. However, when you flip the coin again it faces tails up. Next time the chance is 50%. Tails again. The next chance is still 50% and so on. The past results don’t affect the outcome or chance of the next result.
So casting that skill 6 times, due to chance, it does not guaranteed you should have received 3 copied allies.
Hope that was helpful 
Jeto - Support Team Human 