Yes, there is a possibility that section 44AA and section 44ADA can apply simultaneously. In other words, though the law allows you to declare a profit of 50%, it also mandates you to maintain books of accounts. However, a harmonious construction of the two would be to declare 50% profit as well as maintain books of accounts, though you do not calculate profit as per the books of accounts.
This could occur if your turnover is above Rs. 10 lakhs (thus, triggering section 44AA) but it less than Rs. 50 lakhs (thus, allowing benefit of section 44ADA).
There is an anomaly in the forms prescribed by the CBDT. You do have an option to approach your Assessing Officer to claim the benefit of section 44ADA.
M.Com., CA, LL.B