Comment on BTST/ATST( Buy/Acquire Today Sell tomorrow)
Hopefully the exchanges in the near future will go from T+2 to T+1 for Demat settlement, there is work happening on this presently.
DP charges is per debit instruction, so if you have sold 100 shares of Infy today (irrespective of how many trades you sold it in), you will be charged Rs 13 when these shares are debited from your demat.