Sos: clarification needed regarding obc ncl issue , urgent

Respected Sir/Madam, I have applied for the post of Executive Engineer in a government PSU. My father is retired Junior Warrant Officer (Person Below Officer Rank) from the Indian Air Force and is presently working as a Senior Auditor in the Central Government. Currently also, he falls under the class ‘C’ employee category as his grade pay is 4200/-. At the time of applying for the above mentioned post last year in Dec, I applied under OBC category and I submitted the Non Creamy Layer Certificate of last year as I had a valid one since the annual income of my father from last 3 years (2014-15,2013-14,2013-12) was less than 6 lacs. Now I have to appear for the interview on the 7th September and I have been asked to produce the latest Non Creamy Layer Certificate. As per the latest ITR, the income of my father for the financial year 2016-15 is Rs. 616000, but for the last two financial years it has been less than rupees 6 lacs. So my application for a fresh Non Creamy Layer Certificate was turned down at the Block Office of my native place in Bihar quoting the last annual income of my father and hence I fail the wealth test/income criteria for Non Creamy Layer. But I have read at some blogs that Government employees are granted the status of Non Creamy Layer by the virtue of the class (A,B,C,D) in which they are presently serving. Please tell me if I am still in the non creamy layer or not. If yes then please quote the order of the department of personnel and training that I can produce to get a latest Non Creamy Layer Certificate from the Block office at my native place. Please consider my request to reply ASAP.