So why did the Floureon sensor go into alarm so much sooner than the Kidde? It all comes down to the UL 2032 code for CO detectors. The Kidde sensor is UL listed, which means it was tested (at great expense I bet) by Underwriters Labs to comply with the standard. A good portion of the 2032 standard is about reducing false alarms. My best guess is that the Kidde sensor has software running which will wait a certain amount of time before triggering the alarm.

The Floureon sensor on the other hand isn't listed with any safety agency. They were free to use any false alarm delay they wanted.