Performance Appraisal during Maternity Leave

Sir, I am a PSU employee (working in officer level). During the financial year 2014-15 I have worked till Oct 2014 and afterwards I took maternity leave till end of Mar 2015. Subsequently my boss also retired in the month of Nov 2014. Though he has submitted my performance appraisal report till Nov 2014. A new person has joined as my new boss in the month of Dec 2014, who has never worked with me in the Financial Year 2014-15 I have always scored good ratings in my Annual Performance Appraisal Report (APAR) . Even my ex boss has also given me 80% and above rating for the period of Apr 2014 to nov 2014. Since I was on maternity leave and my new boss has not seen my performance in the said financial year he is keeping me in the bottom line of the bell curve. Now my questions are: 1. Does my new boss has the right to assess me for a period during which he has not at all worked with me? 2. Can my performance be rated on pro rata basis for the duration I have worked with my company, i.e., for the month of apr 14 to Oct 14? Requesting for an early reply.