ITR for doctors who worked on contract basis in a Govt institute

Hi,

I am a doctor and till the last financial year I have been filing returns with ITR-4 and using 44ADA provision for presumptive income.

Last year I joined a Govt institution as a student for a course. I was paid a stipend during this period. After completing the course, I worked in the same institution on contract basis for 6 months. 

My query is whether I am eligible to use the presumptive income provision of 50% for any of these periods, especially when I was working on contract basis.

In my Form 26AS, the amounts for both periods have been paid under Section 192.