Hi seiferm,
Based on my research,it is not able to set the number above 200,The audio bit rate can be any whole number between 20 and 200, inclusive; the default value is 200.The following link is for your reference.
https://docs.microsoft.com/en-us/powershell/module/skype/set-csconferencingpolicy?view=skype-ps
Best Regards,
Leon-Lu
TechNet Community Support
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