Are we sure that "driftdown speed" is scheduled at Vmd and not L/D max? One would assume climb ratio is the overriding concern in a drift down not range.
On the old Tristar (ducks head for incoming) we could choose crit or non crit driftdown depending on if obstacles were a factor. Non crit was for range.
In any case the OEI ceiling alt at "driftdown speed" is higher than OEI ceiling at OEI LRC so on the way down you need to asses obstacle clearance for the level off and ensure 1000ft clearance and then choose to accelerate and descend further if required for range.