Are you using the Duplicate Across Pages command to duplicate the field? Are you adding it using a script? Manually?
At any rate, you can't add it before running the Fields Detection Wizard (if you want to be able to use it, that is).
I am using the Duplicate Across Pages command.
That should be the most efficient way of doing it... One thing you can try, though, is to disable the automatic redrawing of the document while adding the new fields. To do that run this code from the JS Console before duplicating the fields:
this.delay = true;
When done, execute this code:
this.delay = false;
This does appear to have a slight effect on the processing. It still is laborious, but, while this isn't a fix, it is an answer. Thanks!