EZY cost index 6 or 12

[I-WEBA]

Hey everybody!

I just read on the net that EZY cost index usually varies between 6 or 12, and it depends on the specific route.
I'm just curious to know what factors are responsible for deciding cost index 6 or 12?

Cheers.

[de facto]

Airport slot allocations or fuel price would be a difference between two used CIs.

[ESQU]

The difference between 6 and 12 is so small, it barely makes a difference except to a bean counter.