1. Manager have to find the root of problem as why income difference if he thinks 2 team had same factor .
2. Manager never diagnose their own team for expectation result year by year but still keep old performance .
3. Motivation will go down when found the result of income difference and feel company was not fair for them.
4. Manager have to diagnose own performance of team , motivate of team to achieve target , or find another factor that made the result of performance difference such as relevant factor and irrelevant factor .