While I agree that an operating paddlefan will delay the alarm of a correctly placed smoke detector, I don't think anything will mitigate the delay short of not running the fan.
Paddlefans are intended by design, sizing and placement to roll the entire volume of air in a room )unless the room is very large. When the fan is running, the air in the room will be homogenized, not stratified. I don't see where smoke detector placement (within normal parameters) will have any effect.
