Powertop drains battery

In idle mode my notebook Samsung 300E5Z consumes ~10W, but when I launch powertop 2.1 power consumption doubles.

I check power consumption by monitoring
/sys/class/power_supply/BAT1/current_now
(it's value raises from 900000 to 1700000 when powertop runs)

CPU temperature reported by lm-sensors raises by 8 °C after powertop launch.

It does not look like powertop uses CPU much though: top shows <10% CPU usage and according to cpufreq-info CPU stays at 800MHz

As soon as I exit from powertop power usage returns to idle.

Purging and reinstall powertop package does not help. I also tried removing /var/cache/powertop/saved_*.powertop but it did not help, either (BTW, I suppose saved_parameters.powertop should be cleaned by package purge...)

Powertop 1.97 used to work well before upgrade to 12.10

ProblemType: Bug
DistroRelease: Ubuntu 12.10
Package: powertop 2.1-0ubuntu1
ProcVersionSignature: Ubuntu 3.5.0-22.34-generic 3.5.7.2
Uname: Linux 3.5.0-22-generic x86_64
ApportVersion: 2.6.1-0ubuntu9
Architecture: amd64
Date: Sun Jan 20 20:31:22 2013
InstallationDate: Installed on 2012-07-01 (203 days ago)
InstallationMedia: Xubuntu 12.04 LTS "Precise Pangolin" - Release amd64 (20120425)
MarkForUpload: True
SourcePackage: powertop
UpgradeStatus: Upgraded to quantal on 2012-10-21 (90 days ago)