Cowell said he was concerned that GaGa and Madonna's songs were too limiting for the contestants so next Wednesday's X Factor will instead feature a Rock n' Roll theme.
"I changed my mind [about the theme]. What I like about Wednesday's show was the idea of someone, particularly Astro, using the whole stage without props," he told The Hollywood Reporter.
"I thought doing Lady GaGa and Madonna could get a bit too choreography-led and also too restrictive for someone like Astro."
Cowell continued: "Rock music gives you a better chance to use the whole stage like we did on the auditions - just you and a huge platform behind you and make it like it's your first concert."
The X Factor's Thursday results show will feature a performance from Rihanna.
Last night, Stereo Hogzz were eliminated from The X Factor after falling into the bottom two with another of Paula Abdul's groups, Lakoda Rayne.
Remaining acts Lakoda Rayne, Marcus Canty, Drew Ryniewicz, LeRoy Bell, Astro, Rachel Crow, Chris Rene, Josh Krajcik, Melanie Amaro and Stacy Francis will compete for America's votes again next week.
The X Factor USA continues with Rock n' Roll Night on Wednesday at 8/7c on Fox.
> X Factor Stereo Hogzz 'didn't want Paula Abdul to have to choose'
> X Factor USA Lakoda Rayne: 'It was an overwhelming night'
Watch Stereo Hogzz discuss their X Factor exit below: