It would be great to have the ability to use the CUSTOM option when the mode is set to TRANSACTION. All other modes have a CUSTOM option. The TRANSACTION mode contains some details that are not provided in other modes.
@TravisA did you know much of the same functionality in custom mode, can be applied in advanced search also? Advanced search will work within Transaction mode and may help you accomplish your goal. If you connect with your account manager, @nathan.carter he help you if you need more detail!