The back-weighted scheme is also problematic because sets up a perverse incentive to consider letting people go at the end of their second year unless they are all-stars, since the company ends up keeping 70% of that equity and gets 2 years of hard work out of the person. With an even weighted scheme there is no time-dependent tradeoff like this to be made, the employee continually earns shares at a fixed rate and as long as they are contributing managers never have a hard "decision point" to make with regards to their shares.