Hi Bruno,
As I was reading thru your reply, your view - "maybe next year we can think about it for ProPilot v2" is an excellent idea. So this virtual salary should be given only to those who fly using PP. And depending on the points you earn there, or rather for not making mistakes and getting fined you can allocate salary. Something like miles flown * (salary component based on rank)
So FC can have something like .2, the next .4, ... CC around 1 etc. Any penalty that you make will have at FC penalty * .2 amount deducted from the final amount payable. I think a good model to look at is the FS Passenger model.