Stamp duty and Registration charges going to increse by April/2013

Hi,

I have booked one flat one month back in 64 Green Meadows, Marunji, Pune, Now builder is saying that do your registration ASAP, as Stamp duty and reg charges going to increase by 1st April 2013.

Could you please inform me whether this information is correct or builder is just saying for the purpose to get his 20% booking amount.

thanks in advance.

regards,
Dinesh