The number of opening trades counts the number of opening transactions, and NOT the total number of transactions. An opening transaction is a transaction that is used to initiate a new position (i.e. open a condor). Closing trades / expiring trades are not included as part of this count. (open condor + close condor = 1 opening trade)
Each new trade that is constructed from a Strategy Block is considered an opening trade. Each opening trade is automatically correlated with its corresponding closing / expiring trade to track the number of winners / losers / profit / loss for each opening trade.
A spread is considered one trade, regardless of how many legs are part of that trade. For instance, an Iron Condor is considered one trade, even though it has 4 legs.
The total transactions for a strategy will usually be double the number of opening trades, as each opening trade will have a corresponding closing / expiring transaction.
For example, the following has 3 opening trades, even though it it has 6 separate transactions.
Open Iron Condor
Open Straddle
Close Iron Condor
Expired Straddle
Open Put Vertical
Close Put Vertical
For more information, please review: Analyzing Results