Logic Pro 7 allows for plugin delay compensation to be on for ALL audio channels (including normal audio channels, buses, aux sends, instruments, and master channels). However, the default setting for plugin delay compensation is set to include only 'normal audio tracks and instruments'. In order to turn on plugin delay compensation for ALL audio channel types, select 'ALL from the following Preferences menu:
Logic Pro > Preferences... > Audio > General > Plugin Delay Compensation > 'ALL'
This preference panel should appear as in the screenshot below: