Answer
No, MyGeotab does not pull additional data for the columns added on the Data tab. Each report has a predefined set of data pulled from MyGeotab. Adding additional columns do not change this predefined set of data that the report can pull from MyGeotab.
Additional Notes
Reports in the same category share the same predefined data set. For example, Built-in Advanced Audit Log and Default Audit Log report under Audit Log share the same predefined set of data. A user cannot change this predefined dataset by adding additional columns on the Data tab.