Did you write your own service for capturing the response? If so, why and why not use the available service just like you used the container service, which would implement everything for you with the recommended patterns in place already?
The feedback service for capturing the the response has another name and url (company standards). It uses the out of the box activity CaptureInteraction. Some customized mapping (data-transform) was added for control-groups. It uses the .MktType property for ControlGroup and the property MktValue is filled with true/false depending on customerid belonging to the control group or not.