Wide Angel Attachment For Powershot S1 IS Confusion!

[danielswiss]

I see that Canon sells WC-DC52A (for my camera S1 IS) andWC-DC52 for other Powershots (including the A80). The price difference between the two can be as much as $ 100.00. I tried out the WC-DC52 in the store today and it seemed to fit. Does anybody know what the difference is between 52 and 52A and why I should pay 100 dollars more for 52A.