Lurkio - good points all.
When the engines are commanded to operate in a modulated idle condition, is "IDLE" displayed above the EPR gauges?
From FM:
"IDLE Indication Displays green when engines are at idle thrust."
AA757 - I believe you are thinking about the idle input side of the IDLE/PERF inputs entered in the FMGC on the A/C STATUS page. An IDLE input only effects the performance data base in the FMGC - it doesn't have any effect on engine control.