i think this is just like OASW system, some ship exclusively able to go fastest with the standard 1 turbine + 1 amatsukaze boiler while the other didn't. and giving 1 turbine + 1 non amatsukaze boiler to ship that got fastest speed with 1 turbine and amatsukaze boiler did not let them go fastest only fast+
kek, u're right she is just too heavy XDtried turbine + 3x new boiler and still fast+
That is the reason why Iowa is such a fuel (and ammo too, but that's for different reason) hog in Kancolle. Just like how they only really counted the maximum range for naval gun range designation, devs mainly considered Iowa's flank speed for the fuel cost calculation.
SPEEDY SPEED GIRL
Diesel is burning
SPEEDY SPEED GIRL
As fast as she can be
SPEEDY SPEED GIRL
Every night
With the turbines on her slots
SPEEDY SPEED GIRL
As fast as she can be
SPEEDY SPEED GIRL
Every night
With the turbines on her slots