Today I was having position of Banknifty13julfut 50 buy. I placed a basket order two sell orders 1) to close existing jul future and 2) sell 50 banknifty13augfut. I had Rs60000/= and paid in Rs10000/=. Hence Margin required for selling banknifty13augfut only required. What I had sufficient margin. Still augfut order was rejected. Kindly look into this. The problem persists already for more than two months
Firing 2 orders for SAR in market that has gap opening can set you back easily by 30-40 points if not more
About your scenario, I am guessing . . .
Sell 50 BNF Aug part of the basket went in first for execution . . . so rejected as margin less due to Long 50 BNF Jul (was Nrml so full margin blocked)
Happy