Tdr. transfer of development right valuation and income tax calculation

Ours is a co op Hou society in Thane Registered since past 40 years. We are owners of full land as per conveyance deed. Part of the land is ground and Thane Municipal corporation ( TMC) occupied it for many years without any documents of possession Area of ground is 1800 sq mtrs and market value of the land is around Rs 6 crores TMC agreed to give us 1 T D R FSI OUR SOCIETY AGREED TO PART WITH THE GROUND TO T M C in return consideration of FSI TDR OUR SOCIETY AGREED TO HANDOVER TDR TO THIRD PARTY FOR RS 2.25 Crores consideration amount showing market value of TDR AS RS 1 only but consideration of Rs 2.25 crores while registering the agreement and on payment of stamp duty and registration charges on Rs 2 crores Now our society will have to pay tax only on Rs 2.25 crores consideration amount less usual deductions allowed I e purchase price etc Or On market value of TDR. i e Rs 6 crores irrespective of receipt of only Rs 2.25 crores And On payment of tax only on 2.25 crores subsequently tax demand will be raised and we will have to pay tax interest and penalty if any? Thanks