Thanks for the response. I see that my Greek is Weak.
On 04/11/2013, the $ SPX was trading around 1593.
If I understand the delta properly, the May 1620 Puts were selling for 33.80.
The delta was about 71
Today, the $ SPX is trading around 1550.
The May 1620 Puts are selling for 68.70. Buy...