The CSDADC datasheet version 1.30 has an error. The operation (or switching) frequency should be IMO/(VC2xVC1) for VC2 configuration, since the source of the VC2 divider is VC1 itself. This has been fixed in PSoC Designer 5.2.
The CSDADC device is sensitive to EMC signals at the operation frequency and harmonics in VC2 configuration. This configuration is only recommended when you do not plan to run EMC/EMI certification tests.