Pay fixation

Dear Sir, Please guide about the rule of pay fixation for following case: 1. Candidate is a Central Govt. employee & join in the department 02/07/2004. 2. His last pay was (as on 31/01/2011) Rs.12930/- + GP Rs.4200/- in PB-2. (as per 6th CPC) 3. In response to the advertisement published by UPSC in employment news (same department) he applied for higher post through proper channel and selected for the same. 4. After relieving from the parent office dated 31/01/2011 candidate join to the new office (Kolkata) dated 03/02/2011 after availing joining time of 2 days. 5. Though the post carries higher duties and responsibilities (Group B Gazetted) pay is fixed to the minimum pay, i.e. Rs.12540/- +GP Rs.4600/- in PB-2 and date of next increment 01/07/2012 Please suggest the pay fixation process in this case and date of next increment. Thanks & Regards T. N. Rudra