By selecting the "I Prefer Revenue" Preference, you are allowing revenue bearing puzzles to be considered when a puzzle is requested. Therefore, as long as your puzzle Preference is set to "I Prefer Revenue", your site is correctly configured to serve a revenue bearing puzzle when applicable.
Our system analyzes requests in real-time and takes many variables into account when a puzzle is requested. Selecting the "Revenue" Preference allows the system to serve a revenue bearing puzzle whenever it is appropriate. Therefore, the type of puzzles that your users will see depends on the different variables, including how your site and users line up with current advertisers' targets.