Perpendicular Chase Walls are a major planning hazard

Perpendicular Chase Walls are a major planning hazard. Most window companies are going to treat it like any other opening with a 1x buck on the wall without knowing how the interior wall is framed out. At a minimum they typically get at least 7/8" furring channel plus 5/8" drywall for 1-1/2" plus whatever additional shimming the framers need to use to level it out. A LOT of chase walls are 2-1/2" off the masonry, potentially more if there is wood paneling.

With my extensive background in interiors before I became a window expert and then over a decade working on these super luxury homes, I key in on every interior and exterior finish condition on every side of every opening. Each jamb, sill, and head may have a totally different finish condition that has to be planned for and affects the size of the windows and doors.

Wood cladding, stone cladding, stair landings, interior/exterior flooring transitions, pocket framing. Modern design complexity in luxury homes is vastly more complex than it was just a few years ago and most window companies have very little experience beyond putting in the windows.