Cancellation of Registered Lease Agreement

Hi, We have rented out 4th floor of our commercial property (location : Bangalore) to a client under a registered lease agreement. The agreement period was 33 months but the tenant vacated in 15 months. The tenant gave a proper 3 months notice prior vacating. Following are mentioned in the section "Termination of the Agreement" 11.1 The Lease shall be terminable under all or any of the following circumstances 11.1.1 By efflux of time; 11.1.2 By the breach of any covenants/representation by the either of the party during the entire tenure of the agreement including the Lock-in period; 11.1.3 By Mutual Consent of both the parties; 11.1.4 Upon happening of natural calamities /acts of god which might render the lease of the schedule mentioned property impossible; 11.1.5 By liquidation or winding up of the “LESSEE”; 11.1.6 After the completion of Lock-in Period (as mentioned in the Section 1.3 of this Lease agreement), the Lease may be terminated at the sole option of the “LESSEE”, by giving NINETY days written notice in advance to the “LESSORS”. Now, we may say that the lease has been terminated as per 11.1.6 (The written notice was given vide email from the admin of the company). When we are approaching the client for Registration of the "Cancellation of Lease Agreement", the LESSEE says that they cannot bear the costs involved. We enquired for the same through our contacts about the costs involved but we got mixed information as follows 1. Some people said that, Since the agreement period is not fully over, we have to pay the stamp duty equal to the amount which we paid during registration (During registration the stamp duty was 28100/- and registration charges was 14100/-). So, they say that now also we should pay 28100+14100 = 42200/-. 2. Some people said that, for cancellation of lease agreement, the stamp duty will be not more than 500/- no matter if it is being terminated before or after the agreement period. Can you please throw light on to this?? What will be the Stamp duty and Registration charges for the Cancellation of Lease agreement?? Is it having any bearing on the remaining period of the lease agreement?