I would love to be able to see my costs for non-billable tasks without that impacting my revenue budget.

My project budget type is based on project and my billing method is based on staff hours. if I turn on the option to include non-billable hours in cost calculations (in settings), my revenue calculations also include non-billable hours. This doesn't make any sense. I won't bill by client for non-billable hours so why would there be additional revenue? I want to know how much this non-billable work costs because it impacts my project profitability. I wish there was to see this basic metric: Profit Margin= (Revenue-Cost)/Revenue x 100. 

Does anyone else have this problem?