Check shutter settings after correcting shutter reductions
Correct the shutter reduction in the construction preferences, then check or bulk-edit the shutter settings of units already placed in existing designs.
After a shutter reduction is corrected in the construction preferences, newly created designs use the corrected value.
Shutter systems already placed in existing designs keep the values they were built with.
Existing units therefore need their shutter settings checked individually (or corrected with bulk edit).