Render Problems - Clipping when I render Mono File

hey. So I am doing some voiceover stuff for some Skyrim Mods... 

the problem is, that skyrim needs mono files... well that's not the problem.

the problem occours when I try and render a mono output.

Basically I am compressing the vocals, and then using the concrete limiter on the output just to get it right near zero (i have played bethesda games with no sound or music just to hear how they do their voices, they are heavily processed and gated - surprisingly)

so my concrete limiter is set at -0.5 and my master fader is at 0

when i render a stereo file. no problems, no clipping nothing..

i try and render out a mono file and it is now clipping at the louder parts! 

does anybody know what could be happening? I am using all CW effects. (gate and vx64 on the mixer 1) 

here is the project if anybody wants to see if I am doing something wrong...

http://www.elijahlucian.c...hlucian-krundlines.omf