Hi Allison,
You will be able to achieve this with a baseline report. Using the following text mode in one of your columns will return the date difference in weekdays between the Project planned completion date and the Baseline planned completion.
displayname=Planned Comp Variance
textmode=true
valueexpression=CONCAT(WEEKDAYDIFF({plannedCompletionDate},{project}.{plannedCompletionDate})," Days")
valueformat=HTML
You will probably also want to apply a filter to your baseline report for Baseline>>Is Default = True, otherwise the report will return all baselines associated with each project and not just the default one.
Hope that helps!
Best Regards,
Rich.