You are the HR manager of a professional services firm with 300 employees. Your company uses annual reviews along with frequent checkin meetings throughout the year as part of performance management.
Employees are evaluated on a number of questions assessing customer service quality and sales volume (results of a customer satisfaction survey and actual sales metrics, weighted at 60%) and demonstrating corporate values in day-to-day activities (mentoring others, driving change, and creativity, weighted at 40%).
The annual reviews have just been completed, and you heard from Orlando Nicholson, an employee who has been with the firm for 2 years. Orlando has a cordial but distant relationship with his manager. He asked for a meeting with you and revealed that he feels the most recent performance review he received is unfair. Orlando feels that his customer satisfaction scores are modest, but this is due to being assigned some of the most difficult clients the company has. In addition, the manager rated him as average in mentoring others, discounting the fact that he was heavily involved in the onboarding of two new employees 8 months ago. Orlando also feels that his relatively quiet and shy personality is being held against him. He feels that he heavily influences organizational change, but this happens informally and not in big meetings. In fact, there have been several times when he feels that other people took credit for his ideas.
Questions 

1. What would you advise Orlando to do in this meeting?
2. What would you tell his manager, if anything?
3. Are there any systemic changes you could think of that may help prevent instances like these from happening in the future?