1. Sec 50C is for the purpose of computation of capital gains and not for any other purpose.
2. As per 3rd proviso to sec 50C it is hereby clarified that if the value determined by the stamp valuation authority is not more than 105% of the sale consideration then for the purpose of sec 48 actual sale consideration will be used in arriving at capital gains.
3. From the angle of the purchaser as per sec 56(2)(x) stamp duty value should not be more than 5% of the actual amount paid for that immovable property. If this condition is not satisfied and the differential amount exceeds Rs. 50,000 then the same differential amount will be taxed under the head "Income from Other Sources".
Please correct me if the above solution has an alternative view.