Dan, Have you tried comparing New/Repeat segments based on built in visits no. vs getNewRepeat ? I'm seeing odd differences (using discover) suggesting the latter is not accurate (similar finding with other plugins too when compared to equivilant built in metrics )
With the latest release of calculated metrics you can now create segmented metrics for new or repeat visitors (you can define them however you want, most people define it as visit number > 1 and visit number = 1). This can then be applied to any report.