Noob Question about retraining soldiers

[Pode]

It's been long enough that I've forgotten (if I ever really knew) how the experience level of replenishment troops is determined. I remember that the number of chevrons for a unit reflects the average of the chevrons for each individual man, but I thought there was much controversy over whether 1) the replenishment troops started out with 0 experience and thus drug the unit average down, 2) they got a bonus based on the experience of the unit they were going into and thus didn't drag down the average as much, or 3) their experience was set to the average of the guys they were joining. I know it's not 3, at least not all the time, but am unsure how it actually works. Can anyone beat me about the head and shoulders with the clue stick?

[Maksimus]

Well, AI in ALX.exe retrains unit's for you anyway's even If you don't give the order