That is interesting and makes sense. Two thoughts. One, I think it would make more sense to include such a feature as a specially coloured mark to make it easier to scan past it when not used (and find it when desired). Two, on the meters scale it appears that the mark is additional to the 3100 and 3200 marks while on the knots scale the 3.2 knot mark is not emphasized and is level with the other lower marks.
I think the omission of the higher 3.2 mark is unintentional since there is no omission on the meters scale.
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