Is 3 mm expansion with MARPE worth it?

The ortho I saw today for a MARPE consult measured the width of my palate on a scan at a point across the arch (instead of from molar to molar) and said maxilla is 29 mm and mandible is 32 mm. She said the goal is for them to be the same, and that under 32 mm for maxilla is associated with more tongue collapse. Is 32 mm big enough, and will only a 3 mm increase give significant nasal breathing benefits? Thanks for any information.