It is affecting the sallary because your 100% sallary changes with difficulty somehow. That a fact otherwise you will not be able to get such high sallaries for drilling oil ... That's the way of %. You should know it, it's only a question of interpretation (substitution). The base equation must be somewhere like I've wrtitten. Sallary_percent*hours*morale_before*f(diff,LP) where f(x,y) can ignore x when needed, but I highly doubt it, because through my observations it is affecting the sallary in a strong way. But I've not been able to do high end obs till now. I've only adjusted it for stealing horses, drilling oil (as you have mentioned here) and lower jobs. Also maybe the truth is somewhere else . I know my equation would mean that burglary is better than Bounty hunting, but the difference is only 5 $ or so. Edit: Try to look at 100% sallaries from your written results. You will see that 100% is raising up with difficulty.