Dear MrPlus,
I previously set my config within the GUI > updated the config file as below > launched via standard shortcut & "NPlusMiner With ConfigFile"
The problem: If I set GPU0+GPU1 for example, all 3 GPUs still mine. If I set only GPU2, all 3 GPUs mine. If I set GPU1+GPU2 with 'GPUCount 2', GPU0+GPU1 mine.