Adding name to birth certificate

My son was born 6 years ago and when I approached the office for a birth certificate, the nice gentleman took 100 rupees from me and never gave me any change. He gave me a certificate without my son's name and told that can be added later as per what is put in the passport. He told me that is a 'best practice'. Now if I want the name added, I know I have to pay an additional 'fee'. I am uncomfortable. Is there a way of doing it without 'additional' payments.