CA exam day to be included in extension or not

I have given Nov 2017 ca final exam but didnt cleared so i will be giving may 2018.

I have extension assuming of either 30 days or 10 days. would ca final exam days for may 2018 i.e 2nd attempt be included as leave or as a working day. if I have 30 days extension, can i say to principal i will serve 14 days and 16 days are working because of exams?
please give reference