You are having a problem comparing these positions. Take the four legs from both strangles. Add them to make a single position. That position is a box. A box is a riskless (ok, there is pin risk) position that varies very slightly in price as time passes (or interest rates change) by the cost of carrying the position to expiration. Next, break that box into a call spread and a put spread, instead of two strangles. It's easy to see that at expiration, no matter what the price of the underlying, the call spread plus put spread equals the distance between the strikes. Thus, the price of the box is constant. That means the difference between the two strangles is always the value of the box. Sell either one and the P/L is identical - assuming you collect the value of the box as the extra premium when selling the ITM strangle. Mark