I think that lost salary is a factor in the calculation only if you are initially comparing the profitability of getting a license to other options, like staying in your current job and burying your dreams about a pilot career. I think that most that participate in this thread have already made that decision and are only interested in the actual costs and how to minize them. If you have already decided to get that license, the income during training is lost no matter what and can be eliminated from the calculation.