This is a good tactic but not always something people can implement and some folks would be best doing a mix of those. Of course, for us exempt folks, hours and income do not completely tie in terms of a strong coefficient of determination.
This talk reminds me of my concept of GPAPH back in school. If someone put ten hours into a project and got 95%, and I put in one hour and got 93%, my grade point average per hour far eclipsed theirs. People often focus too much on merely one metric.