You can settle your sale obligations of your own through a Delivery instruction to your DP. But you have the risk on knowing the settlement number , PAY-IN dates (some times two settlements will have a PAY-In on same day). So it is better to execute POA and as all the transactions are trackable you will easily know the movement of shares as well which you execute if also not a general POA it is called Specific POA where it will be used only for the exchange PAY-IN obligations and not for any OFF-Market Transfers.
Also Seed-E facility from NSDL is a facility of executing instruction on its site after you login. This facility is also charged with an AMC as well as none of the BO can transact directly with NSDL or CDSL they are the depositories and all the Beneficary Owners should approch only the concern DP (depository partifcipants)
Last, if you dont trust your member broker then better shift
Regards
SunilMogan