Thank for your reply. To answer some of your questions:
I found no errors in the gatherer (only warnings because of deleted items).
Until know i couldn't find out which ones could be missing - but there shouldn't be any exact duplicates. Also there hasn't been an update of this content type.
I know that there are about 550 items, because i can count them in MS Access (and also count them in the list) - and in this list the only allowed content type is "features".
But the number seems to be fixed, because i added some items the last days - and the sum in the scopes (and because of that in the search results) remains "512". Searching for contenttype:feature doesn't return alternative results.
Do you have any additional ideas why scope display numbers can be "off"?
- Johannes