What does PS3UNITS mean?

Hey, when I first read this stock, I bought short, thinking there is no way this stock could come true. After all, the PS2 sold over 150M units. When I reread the stock just now however, I interpreted it differently.

"Sony's chief executive Kazuo Hirai predicts that PlayStation3 will outsell its predecessor, the PS2, despite the fact that it's currently the video game underdog. Why the cheery outlook? It might have something to do with last month's sales. After the Metal Gear Solid 4 bundle was released in June, PS3 sold 405,500 units, which surpassed Xbox 360's sales two to one. Sony also launched a new version of PS3 last week, which will have an 80 GB hard drive, but will still only cost $399. The PS2 sold 140 million units in the eight years since its release. Hirai has put a goal of 150 million units on the PS3-is it only a matter of time?

"This proposition will pay off at POP$100 per share if more units of the PlayStation3 are sold than the PS2 by January 1, 2010, as reported by the research firm iSuppli."

Does this mean that the PS3 must sell more cumulative units by Jan. 1, 2010 to pay out? Or does this mean that by Jan. 1, 2010 the PS3 must be selling more units per week/month/whatever then the PS2 is?