I try to tell it in a way that a friend of yours can support you.
Most likely you have Mic 9 and 10 still configured as stereo channel.
You need to configure these 2 channels in TotalMix FX as Mono channels.
In TotalMix FX "Top Row":
1. click to the "tool icon" of the Stereo channel "Analog 9/10"
This opens the channel settings.
You will see there an Orange Button "Stereo".
2. Click to the Stereo Button
This will split the Stereo Channel into 2 Mono Channels.
From there on you will hear Input from the mono channels Mic9 and Mic10 on left and right output channel.
Don't forget to save this into your snapshot and workplace.
Good luck implementing it and have fun using it cankirca.
BR Ramses - UFX III, 12Mic, XTC, ADI-2 Pro FS R BE, RayDAT, X10SRi-F, E5-1680v4, Win10Pro22H2, Cub13