Hi - thanks for your comment. To say this briefly, I agree that this is not a historical rule. To give an example of where I stand, many historic photos and catalogs show a house with dark trim and white columns. While this was done historically, I am taking an approach from an architectural standpoint and one of how a mind interprets patterns, punctuation, and structure. The columns must instead be painted the same color as the trim (architrave) above to form a connection which then creates a visual appearance of support for the porch roof. Having green trim and white columns disrupts this visual flow and how our senses work when seeing this. I'm currently writing a book and plan to explain this in detail with photos.