Left 4 Dead players will soon get experience Crash Course, the new downloadable campaign from Valve. The campaign, which bridges the story gap between the No Mercy and Death Toll campaigns, will be free for the PC but 560 Microsoft Points for the Xbox 360.

While the Survival Pack DLC was free for both platforms, Valve says that the price tag on the new campaign was Microsoft’s decision, “We own our platform, Steam. Microsoft owns their platform. They wanted to make sure there’s an economy of value there,” Left 4 Dead writer Chet Faliszek told Eurogamer. While Microsoft may have pushed for a price point, Valve didn’t look at this as a way to rip off players, “It’s not like [Valve is] looking at this as ‘we need some money, we’re going to charge,’ obviously, or we’d do it on the PC. So it’s just kind of the way the system works right now.”

Crash Course is still confirmed for a September release but there is no word on whether or not it will compatible with both the original Left 4 Dead and its sequel shipping two months later.