Re: 100.14.11 and geforce 7025
X (and the nvidia driver) are doing exactly as you've configured:
(**) NVIDIA(0): Option "MetaModes" "CRT: 1280x1024_75 +0+0, DFP: 1280x1024_75 +1280+0"
If you don't want any overlap between the display devices, then you should remove all the offsets from your Metamodes.
Also, please note that there are an infinite number of X configurations crossed with hardware combinations. They cannot all be tested.