Stamp Duty Charge Bangalore

I recently finalized a flat and the builder has quoted 5.15% for stamp duty. I read in the newspaper that the Karnataka Government has reduced the stamp duty from 5 to 3% for property costs between 21 to 35 lakhs. My flat sale value is 30 lakhs. When I checked with the builder, they say that there is no change in the gazette as of now hence no change in the registration charges.