The "Status" is showing when the last data was received from the sensor. This is 18 seconds for the 5n1. This relates to how quickly you can stream data to myAcurite and wunderground.
The file transfer interval is how often data from the internal logger in the display is written to a CSV file on your PC. The internal logger records data every 12 minutes, so a 60-minute transfer interval would write 5 sets of data to the CSV file.