Hi appreciated your arguments
OP is running Wheezy. Wheezy is like most distros of the Xorg automagic years. Its 'Xorg -configure' generates an xorg.conf loaded with litter
Some newer Intel chips _do_not_ work with the older Xorg and it is recommended to get the newer drivers and X software. Perhaps it would be easier for OP to upgrade.
By not working I mean - for one display it works, but all the rest doesn't. Perhaps OP should check if Xorg in the version (s)he uses supports the hardware properly.
regards