The hourly rate used is currently only available by back-calculating from Resource Revenue (Resource Revenue / Hours). However, this does not make it easy to tell which rate sheet the hourly rate was pulled from.
Ideally, the numbers and rate location behind Resource Revenue should be exposed as fields available for reporting:
Is it the Default, Company, or Project rate?
If Company, which one?
The hourly rate directly cited that is being used by that hour record.
This is something that bothers our finance people from a surety-of-data perspective, especially as convoluted as we feel the financial aspect of Workfront is.