query in 44BBA

Special provision for computing profits and gains of the business of operation of aircraft in the case of non-residents.

1. Sec 44BBA deals with the taxation of income on presumptive bases for non-residents carrying Aircraft business in India. 
2. This section is not optional and it is mandatory for any non-residents who are carrying on aircraft business 
3. Any amount which is paid or payable to the non-resident or to a person on his behalf or amount received or receivable to the non-resident or on behalf of the assessee in relation to carriage of passengers, livestock, mail or goods from in India or outside India respectively. 
4. 5% on the above amount for the year will be considered as profit chargeable under the head PGBP to the non-resident and no other expenses or depreciation will be allowed. 
Please correct me if the above solution has an alternative view.