Potential Income
In order to better judge your results for Real Income, you need to know what your Potential Income is.
That is, if you absolutely squeezed every last billable hour possible out of the agency and into invoices, what could your maximum Real Income theoretically be?
Then you can have a discussion about the Income Gap. Where do you lose income between your potential income becoming your real income?
You will never have an income gap of zero, and there is real value to be gained in making incremental improvements by examining where the 'waste' happens.