audit u/s 44AD

With respect to section 44AD,it is applicable only when showing the net profit as atleast 8% from total turnover and pay tax. No deduction allowed. If we are not ready to show atleast 8% profit then audit is required(section 44AB). If audit is required then book of accounts need to be maintained then only auditors can audit (section 44AA). Then there is no value for section 44AD here. I think we should not see anything thru the prism of section 44AD. what will be effect if we follow normal provisions of PGBP and not as per 44AD.