The comics publisher has decided to delay scheduled price drops by four weeks.

Source: Comixology Support

Comixology users have discovered that DC is no longer discounting month old titles, beginning with comics released on May 1st. Previously, DC dropped their prices by a dollar on all issues more than a month old. Users of the digital comic software discovered the change today when preparing to buy some of DC's titles. When discovering that prices were still at $2.99 (and $3.99 for a few books) and complained to Comixology, whom informed them that DC had issued the change.

@bantharo23 If you're referring to DC books, price reductions happen after 8 weeks. — comiXology Support (@cmxsupport) June 5, 2013

@bantharo23 Sorry, but that's no longer the case. (since May 1st) — comiXology Support (@cmxsupport) June 5, 2013

@quisp27 we just do as the publishers wish with regards to price changes. — comiXology Support (@cmxsupport) June 5, 2013

Looking through Comixology's twitter accounts, I was unable to find any announcement prior to today that the price change was occuring. Also, this appears to be the first week that the price change policy is affecting readers.

So, if you're a digitally saavy DC comics reader and you're looking to save a bit of money on DC's comics, prepared to be two months behind instead of one.