While I was flying with 10+ year Airbus 320, IAE engine with EPR, I saw a constant difference between N1 parameters around 2%. I checked the Engine Hours and Engine Cycles that they are almost the same. Oil consumption of a greater N1 valued engine was less than the other one.
So why N1 parameters different? is it a sign of an engine part problem?
Note: 2% value difference at cruise level, on the ground it is around 1%