Pay protection of central govt employee who wants to change job from higher level to lower level

Respected Sir, Please reply to my below queries as it is matter of my career. I would like to know what are the revised pay fixation rules (after 7th pay commission) for transfer of an official working as Assistant Audit Officer (Level-8) in Indian Audit and Accounts Department with current basic pay of Rs. 49,000 to Income Tax Department as Income Tax Inspector (Level-7) considering the following information: a) Application was rooted through proper channel and Permission to apply for Combined Graduate Level Exam (CGLE) 2016 (which includes Income Tax Inspector Post) conducted by Staff Selection Commission was granted by the competent authority in March 2016 (before exam) and the official at that time was in level 5 (Auditor, Grade Pay 2800) and b) In meanwhile the official cleared departmental exam in January 2017 and in March 2017 he joined as Assistant Audit Officer (Level-8) with pay of Rs. 47,600. In August 2017 the official got selected as Income Tax Inspector through CGLE 2016 (Joining expected in July-August 2018). Then the official got next increment on 01.01.2018 and his current basic pay is Rs.49,000 (2) Is the official in the above case, eligible for pay protection, carry forward of leave account, lien and benefit of past service. Guidelines/Rules ,if any, may please be mentioned in the reply (3) Is the Office Memorandum No.12/1/2016-Estt(Pay-I) dated 31.March.2017 : Fixation of pay in case of employees who seek transfer to a lower post under FR 15(a)- clarification regarding, issued by Government of India Ministry of Personnel, Public Grievances and Pensions, Department of Personnel and Training applicable in above case? (4) If not, kindly state the reason and other applicable order/clarification ,if any, may please be mentioned in the reply. (5) If yes, will the pay of the above official (as per above Office memorandum) on joining at Income Tax Department be fixed at Rs. 49000 in Level 7 with next date of increment 01.01.2019 Thanks in advance, Aananya