The platform does not imitate the AWS Billing console. CloudHealth reports show costs at the most granular level possible.
Credits and costs don't cancel out in the visualizations, but will cancel out in the totals shown in the table below the visualization. Each service will be represented as a positive or negative value individually.
To see credits and costs cancel out in reporting, change the category from Service Item or AWS Service to Accounts. This will consolidate costs and credits and automatically sum them together, showing you the billed cost per account.