[BetterBatteryStats] mag01:
That's what I get for logcat -s SystemAppInstaller:V

--------- beginning of /dev/log/system
--------- beginning of /dev/log/main
I/SystemAppInstaller( 2052): Checking if com.asksven.betterbatterystats is a system app
I/SystemAppInstaller( 2052): Command returned /system/priv-app/com.asksven.betterbatterystats*: No such file or directory
I/SystemAppInstaller( 2052): Checking if com.asksven.betterbatterystats is a system app
I/SystemAppInstaller( 2052): Command returned /system/priv-app/com.asksven.betterbatterystats*: No such file or directory
I/SystemAppInstaller( 2052): Checking if system is mounted rw
I/SystemAppInstaller( 2052): Mount status: ro
I/SystemAppInstaller( 2052): Remount system rw
I/SystemAppInstaller( 2052): Checking if system is mounted rw
I/SystemAppInstaller( 2052): Mount status: rw
I/SystemAppInstaller( 2052): Checking if system is mounted rw
I/SystemAppInstaller( 2052): Mount status: rw
I/SystemAppInstaller( 2052): Status: Mounted system rw
I/SystemAppInstaller( 2052): Installing app as system app: cp /data/app/com.asksven.betterbatterystats* /system/priv-app && chmod 644 /system/priv-app/com.asksven.betterbatterystats*
I/SystemAppInstaller( 2052): Checking if com.asksven.betterbatterystats is a system app
I/SystemAppInstaller( 2052): Command returned /system/priv-app/com.asksven.betterbatterystats_xdaedition-1.apk
I/SystemAppInstaller( 2052): Status: Install as system app
I/SystemAppInstaller( 2052): Checking if com.asksven.betterbatterystats is a system app
I/SystemAppInstaller( 2052): Command returned /system/priv-app/com.asksven.betterbatterystats_xdaedition-1.apk
I/SystemAppInstaller( 2052): Checking if system is mounted rw
I/SystemAppInstaller( 2052): Mount status: rw
I/SystemAppInstaller( 2052): Remount system ro
I/SystemAppInstaller( 2052): Checking if system is mounted rw
I/SystemAppInstaller( 2052): Mount status: ro
I/SystemAppInstaller( 2052): Checking if system is mounted rw
I/SystemAppInstaller( 2052): Mount status: ro
I/SystemAppInstaller( 2052): Status: Mounted system ro. Finished
I/SystemAppInstaller( 2052): Checking if com.asksven.betterbatterystats is a system app
I/SystemAppInstaller( 2052): Command returned /system/priv-app/com.asksven.betterbatterystats_xdaedition-1.apk
I/SystemAppInstaller( 2052): Checking if com.asksven.betterbatterystats is a system app
I/SystemAppInstaller( 2052): Command returned /system/priv-app/com.asksven.betterbatterystats_xdaedition-1.apk

by the way this is how uninstall as system app virtually fails for me, I think it's because there are open handles at that time when it tries to remount to read/only because at least the BBS GUI process is still running at that point:

--------- beginning of /dev/log/system
--------- beginning of /dev/log/main
I/SystemAppInstaller( 2856): Checking if com.asksven.betterbatterystats is a system app
I/SystemAppInstaller( 2856): Command returned /system/priv-app/com.asksven.betterbatterystats_xdaedition-1.apk
I/SystemAppInstaller( 2856): Checking if com.asksven.betterbatterystats is a system app
I/SystemAppInstaller( 2856): Command returned /system/priv-app/com.asksven.betterbatterystats_xdaedition-1.apk
I/SystemAppInstaller( 2856): Checking if system is mounted rw
I/SystemAppInstaller( 2856): Mount status: ro
I/SystemAppInstaller( 2856): Remount system rw
I/SystemAppInstaller( 2856): Checking if system is mounted rw
I/SystemAppInstaller( 2856): Mount status: rw
I/SystemAppInstaller( 2856): Checking if system is mounted rw
I/SystemAppInstaller( 2856): Mount status: rw
I/SystemAppInstaller( 2856): Status: Mounted system rw
I/SystemAppInstaller( 2856): Uninstalling system app: rm /system/priv-app/com.asksven.betterbatterystats*
I/SystemAppInstaller( 2856): Checking if com.asksven.betterbatterystats is a system app
I/SystemAppInstaller( 2856): Command returned /system/priv-app/com.asksven.betterbatterystats*: No such file or directory
I/SystemAppInstaller( 2856): Status: Uninstall as system app
I/SystemAppInstaller( 2856): Checking if com.asksven.betterbatterystats is a system app
I/SystemAppInstaller( 2856): Command returned /system/priv-app/com.asksven.betterbatterystats*: No such file or directory
I/SystemAppInstaller( 2856): Checking if system is mounted rw
I/SystemAppInstaller( 2856): Mount status: rw
I/SystemAppInstaller( 2856): Remount system ro
I/SystemAppInstaller( 2856): Checking if system is mounted rw
I/SystemAppInstaller( 2856): Mount status: rw
I/SystemAppInstaller( 2856): Checking if system is mounted rw
I/SystemAppInstaller( 2856): Mount status: rw
I/SystemAppInstaller( 2856): Status: An error while remounting system to ro. Aborted
I/SystemAppInstaller( 2856): Checking if com.asksven.betterbatterystats is a system app
I/SystemAppInstaller( 2856): Command returned /system/priv-app/com.asksven.betterbatterystats*: No such file or directory
I/SystemAppInstaller( 2856): Checking if com.asksven.betterbatterystats is a system app
I/SystemAppInstaller( 2856): Command returned /system/priv-app/com.asksven.betterbatterystats*: No such file or directory