Apple on Thursday modified the terms of the CD-RW promotion to say the deal will end Friday. Until earlier in the day, the same offer was slated to run through Sept. 3.
As previously reported, Apple plans to cut PowerBook prices Saturday by $400 to $500, depending on the model.
An Apple representative was not immediately available to comment.
In the fine print of the mail-in offer, Apple does note that it "reserves the right to change the terms and conditions of the promotion at any time without notice."
The Titanium PowerBook G4 has been popular since Apple introduced it in January. However, the Sept. 3 rebate termination, and the impending price cuts, have fueled speculation that the company may upgrade the notebook soon.
Apple said Tuesday that CEO Steve Jobs won't introduce any new hardware at the Apple Expo Paris event at the end of September. However, a company representative would not say whether the same holds true for Apple Vice President Phil Schiller, who is giving a keynote address at Seybold Seminars, a graphics industry trade show that takes place the same week in San Francisco.