Registration of Actual Sale Deed

I bought a site from a housing society on lease cum sale basis in 1980. LCS deed and conditional sale deed were executed and the same was registered. We built a house in 1985 and have been living there for the past 30 years. I did not take the absolute sale deed but. I got the same from the society in 2012. I went in to get the registration done when the sub registrar asked me to pay at the current market price of the site which was Rs 40 lakhs. The fee however is 1 % of this which comes to Rs. 40000 only. Is the demand valid according to law?