we suggest the clients to do the add frame for the window shutters if the window architraves not looks good by the measurement(over 5mm difference compare top to bottom,left to right)
why? because the architraves are not square/even anymore (also for some new house),its bit hard to installed the shutters in nice place.
the gaps may different on sides,
the added frames are cover the old architraves, make the window square and nice easy to fit the plantation shutters in,
make the outlook more 3D