From what machine translation tells me, Tenshin Amagurin has decided to externally downgrade Shigure a notch because they think she would fit in better as K2 within their Nishumura unit as opposed to K3. Externally because she still has K3 stats according to the above (kind of like Comiching keeping their Asashio in base form when IMO there are signs she is actually K2).
Updated