@ Which percentage use

Say turnover is X.

of which cash turnover is XC

& turnover by banking channel is XB; So total turnover = [XB+XC]

So the minimum profit as per sec. 44AD that is arrived at is 6%(XB)+8%(XC).

Assessee can declare more profit than above minimum stipulated.

5% comes under sec. 44AB, which if you require can be explained, but its not connected with sec. 44AD of IT act.