Plants do require N through flower. Cutting the N out reduces part of the building blocks that make those beautiful buds.
Nitrogen is vital because it is a major component of chlorophyll, the compound by which plants use sunlight energy to produce sugars from water and carbon dioxide (i.e., photosynthesis). It is also a major component of amino acids, the building blocks of proteins. Without proteins, plants wither and die.
I suggested to remove the calmag because your veg nutes would have Ca and Mg in it. By reducing or eliminating the veg nute you have basically dropped out the required micro nutrients as well.
I wouldn't change anything now since you're close to finishing but something to keep in mind for your future grows.
Hope that explains things better.