JTS Wolfpack - Started Scenario - Visibility

[Lethal]

The Started scenario is at night and the indicated visibility range is 3.5nm.  

Enhanced Submarine Rules - Reduced night spotting

At night, the maximum spotting distance to see a submarine on the surface is halved.
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However, in the scenario the Flower Class Corvette, Penstemon spots the player UBoat on the surface at 3.5nm.

Is this a bug or something I am missing?

As the visibility is displayed in orange it may mean that the UBoat spotting is 3.5nm but this is not the case for the blue side(?).  It is logical from programming but not from reality I suggest!  (Remembering this is pre-radar).

StartedImageAtSpotting