Combining Permissions in TiM always gives a person all of the abilities for each Permission. Some combinations of Permissions create additional, unique access.
For example, if a person with Invite/Manage Permission is also granted Edit: Rate Guide/ Acct. Codes Permission, within an Invite they will be able to see the Accounting Codes area and enter account codes as necessary. They will also be able to view or edit account code information from Crew Management by clicking "edit account codes."