Shift a performance mangement system

The plan is to create like a plan to shift a performance mangement system - appraisal from the current we have to a more challenge one.

The one we have is Management by objective yes , but based only on the manager to evaluate the employees. Less impact of the employee.

There are two level of the input ( manager and employees )
for managers its goals and competencies weighted 70 to 30 %
for employees goals and GPI or general performance indicators ( set of 5 each one weight 20%). the goals is weighted 50% of over all and the GPI is worth 50 %)

After ranking - a calibration will take place to reflect on the bell curve normal distribution and will be on the follow scale

Does not meet expectation ( 1) represent 5% on the curve - achieve less than 60%
meet some expectation ( 2) represent 15 % - achieve 60- 70%
meet expectation ( 3) represent 50% - achieve l 80- 100%
Exceed expectation ( 4) represent 20% - achieve less than 101- 119%
Outstanding (5) represent 10% - achieve less than 120% and above