i idle at about 6 mA with and without n9-button-monitor. ive tested it numerous times, under many different circumstances.

what numbers are you getting? if you dont have numbers, heres a good test:
1) install lpsmagic
2) uninstall n9-button-monitor completely {apt-get purge n9-button-monitor}
3) reboot
4) without doing anything else, lock the phone and observe the battery usage every 2 minutes over the course of 10 minutes
5) install n9-button-monitor
6) reboot
7) without doing anything else, lock the phone and observe the battery usage every 2 minutes over the course of 10 minutes

i get the same numbers for 4) and 7) in openmode on pr1.3, namely 6 mA average, with a high of 13 mA and a low of 4 mA.