NOTE: This graph assumes the strategy was established for a net credit.
You can think of this strategy as embedding a short call spread inside a long call butterfly spread. Essentially, you’re selling the short call spread to help pay for the butterfly. Because establishing those spreads separately would entail both buying and selling a call with strike C, they cancel each other out and it becomes a dead strike.
The embedded short call spread makes it possible to establish this strategy for a net credit or a relatively small net debit. However, due to the addition of the short call spread, there is more risk than with a traditional butterfly.
A skip strike butterfly with calls is more of a directional strategy than a standard butterfly. Ideally, you want the stock price to increase somewhat, but not beyond strike B. In this case, the calls with strikes B and D will approach zero, but you’ll retain the premium for the call with strike A.
This strategy is usually run with the stock price at or around strike A. That helps manage the risk, because the stock will have to make a significant move upward before you encounter the maximum loss.