My best guess is that that "black" stuff (which I hate) is similar to roof shingle adhesive. Comes in tubes like cualk. I can only guess that it is easier to remove the grey panels from it verses elastomeric.
Pull them up, remove all the black stuff, make sure the drain holes in the wells are clear and big enough for complete drainage then seal them down with elastomeric. Use a countersink and add another screw exactly between the existing ones and seat them with elastomeric.
You'll never have to pull the boards again.
