It's worth noting here that US 40 Scenic is not actually a state highway. And thus, SHA has no official definition of it.
The HLR log doesn't even mention it at the MD 144 intersection, it's just "CO 1036 NATIONAL PIKE".
So, signs are all we really have to go by, and, well, in the face of some slight inconsistency I'm inclined to stick with the logical option of having the route actually return to US 40 itself rather than randomly end a tenth of a mile or so past the turnoff to it.
Either way it has a short MD144 concurrency so no clinchable mileage is gained or lost.