Definition: Cumulative Cost Basis
Cumulative Cost Basis = Amount / Quantity
This can be considered your breakeven cost for the open Position package. In other words, if you closed out the currently-open Legs in this Position for this price, your Position would breakeven before fees.
The long stock position was opened for debit of $79.46. An Aug 20 85 call was sold initially, then rolled down to a 82.0 then to 80. The net Cumulative Cost Basis of the whole position is $74.58, an improvement of $4.88 over the initial stock trade.
Although Wingman displays the Cumulative Cost Basis for the 85 and 82.5 positions as Closed, the credits received from these positions are included in the Cumulative Cost Basis for the entire position.