Full Screen Mode Gamma Correction in-game setting help

[Tetsuos]

My monitor is calibrated nearly perfectly using a ColorMunki Display colorimeter.

So, my question is, should the in-game setting "Full Screen Mode Gamma Correction" be set to "0" since my monitor is calibrated correctly already? Or should it be left at the default value of "50" to achieve the correct gamma of 2.2 in-game that my monitor is calibrated to?

My gut tells me that it should be set to "0" because I shouldn't need full screen mode gamma correction if my screen is already calibrated correctly. But my gut is probably wrong so would like to hear from someone that knows the correct answer.

Thanks for the help if anyone knows the correct answer.