You may actually be a little better off as-is.
Against the wall, the C will get more bass reinforcement. You are using room correction, so any extra boominess will be removed, and this will lower the C channel amplifier output.
A better question is, how well do you think the sound is integrated? Do you hear a distinct C channel, or does it flow seamlessly from L to C to R?
Also, C channels tend to have narrow L to R dispersion, so they are not as affected by side walls, an important thing for your L and R speakers.
Against the wall, the C will get more bass reinforcement. You are using room correction, so any extra boominess will be removed, and this will lower the C channel amplifier output.
A better question is, how well do you think the sound is integrated? Do you hear a distinct C channel, or does it flow seamlessly from L to C to R?
Also, C channels tend to have narrow L to R dispersion, so they are not as affected by side walls, an important thing for your L and R speakers.