I have a vague recollection that @Bluefrog has recommended here not to do that as DEVONthink might sweep in from the Global Inbox before the other app done with it, e.g. OCR or something. My recollection may be wrong, of course.
Belt and braces, I do what the OP wants by sending all my scans to a folder called “Scanner Output” and then I have Hazel or my fingers on keyboard handling them into DEVONthink. Hazel puts into Global Inbox, and manually I simply drag and drop most of the time. I don’t have an over-whelming volume that precludes this approach.