When you enable the Hourly Wage feature it allows you to enter you hourly wage for each entry from the Tips page. The hourly wage will default to what you save on the Settings page so that you don't have to enter it for every tip. You can change the hourly wage in case you worked a different job.
Here are the changes to the app when you enable hourly wages.
The Wage field is displayed on the Tips page enabling you to save it with your Tips.
Your wage is now calculated by multiplying it by the number of hours you worked.
Your total take home now includes your wages on every calculation in the app.
If you no longer want to track your hourly wage simply disable it from the Settings page.