1.3 instead of 1.6 EPR sounds a large error...... But a very plausible explanation. Does it have any substance or is it just a rumour?
Some years ago, a certain Big Airline was contracted to do charter flights for the military. One day one of their 747 crews entered the RW length as 12000 ft instead of 10000. The a/c only just managed to become airborne.......