I think its better than this method Important - Manual Procedure For Download Software In TATA(SKY HD+ When Error Occurred. | Entertainment : DTH , Telecom and Technology Discussion Forum
its always risky to connect T to single STB . The signals power is not splitting in the T and both tuner sends the power to LNB in this method . so better to remove 1 cable instead of connecting both.
I didnt saw the HD + STB but as a calculation this is my opinion.
i m too lazy