You talking about the factory narrow band vs a wide band?
They are are different type of sensor.....
Anyway, I'm sure if I could be bother ed I could work out the time it takes for the exhaust to travel a meter inside your exhaust pipe at say 4000rpm, but I'm so sure it would be such a miniscule amount of time it wouldn't matter to anyone.
Being able to put the sensor into the factory location is slightly helpful for mounting it, but ad far as accuracy and speed goes I don't think there would be any noticeable difference in wither location.
The factory narrow band sensor is closer as it has to be warmed up by the exhaust. Not for accuracy.