20 July 2021
Yes, you need to club turnover of both HO and branch to arrive at aggregate turnover to determine periodicity for filing return. In this case aggregate turnover would be >5cr and hence provisions applicable to persons having turnover >5cr would be relevant.
25 July 2021
While determining the limit of Rs. 5 crores aggregate turnover is to be seen which is PAN wise. Therefore both the turnover needs to be clubbed. Therefore for you due dates will have to be seen for person having turnover above Rs. 5 crores