[Graham Boak]

What was misleading people in the Fisken photos was not that the band was darker than the base colour of the aircraft, but that the overspray of white had affected the base colour beyond the tape, so there was an immediate contrast followed by a gentle fading back - this misled the eye into seeing a dark band where none existed. The same effect could be happening on the Neutral Grey. I think this is likelier than the tape having stripped paint - the primer (zinc chromate based) being lighter than the topcoat anyway.

However, not having seen the photo....