First off, let me say that the only real authority on this question is the DT staff, so your best bet is to contact support directly about this (which they'll probably tell you soon in a subsequent message).
That being said, to sell products of this type this company would need to have purchased a P-EL license. If no such license has been sold for this image on DT or another site, then they are most likely using the violating the requirements of the license they purchased.
As for the image license fee they're charging, I'm not sure whether they're using that term to mean the same thing that microstock agencies do. That's one of the reasons to get DT's input directly.
mm, Sigma 105 mm macro...