I think you're right. I think what confused me was the phrasing here:

"After 15 days, Audio Hijack will nag you to register at launch and will quit after 15 minutes. Additionally, the recording feature will be disabled."

"Instead, from day one, the app was limited to 15 minutes of recording."

My brain didn't make the jump from "the app quits after 15 minutes" to "the app is limited to 15 minutes of recording."