"Both on facts and in substance, it could not be stated that there were no anomalies in the records and it was completely fallacious to state that there was "only one omission" in one branch," the defence ministry said in documents obtained through RTI.
It has been contended that the confusion over Gen Singh's date of birth issue is due to the military secretary branch, which on the basis of his UPSC form for entry into the National Defence Academy, has recorded May 10, 1950 as his date of birth.
The ministry said that an earlier RTI reply, in which the Legal Adviser (Defence) had accepted army chief's age to be May 10, 1951, had to be "abrogated" as army's adjutant general's branch "had not provided full facts" before the officer.
The defence ministry said that it was told by the Attorney General that the amendment of the date of birth is not "legally tenable" and the issue cannot be reopened at this stage on any basis whatsoever.
The ministry has declared as "null and void and non est" and "unauthorised and illegal" the change in the date of birth to May 10, 1951 in Gen Singh's service records made by a branch of the army in February this year.
It has said that May 10, 1950 will be treated as his official date of birth, which will deny him an extra ten months in office.
In reply to a Rajya Sabha query, Defence Minister A K Antony has said that Gen Singh's last three appointments were made on the basis of his May 19, 1950 date of birth only and accordingly he had a little over eight months left in service.
The AG's branch has now sought clarification from the Defence Ministry on the legal justification of its order and has not yet changed Gen Singh's date of birth in its records.
The army chief has also filed a statutory complaint to defence minister against the ministry decision to reject his contention.