I started to build up my December option inventory in the last couple of trading days. But I made an trade order error when placing an order for SPX IRON Condor: my new long strike of Dec$1445c happened to cancel my existing short strike Dec$1445c. I noticed it after the order was filled and the P&L dropped a couple of hundred dollars in the analyzer. The margin requirement also increased $2000 more than what's normal. So I did two more verticals to get the margin back to normal and formed two IC for the SPX position. This error will probably cost the portfolio around $100, considering the transaction cost, commissions and market price drifts.