Composite scheme

I am a work contractor and following the composite scheme wherein I need to pay only 40% of the value. I want to know if the 40% is below 10 lakhs, still I would need to pay tax. Meaning is exemption of 10 lakhs available to me if I'm going under the composite scheme. And if yes the exemption is available then 40% of the value needs to be considered for determining 10 lakhs limit or the entire value.