The flat and matte will appear the same. Thank you Michael. That's exactly what I needed to know. DH and I had a long discussion about this last night. We did some sample areas throughout the house and have lived with them for a few weeks. He surprised me - he definitely wants to go with white ceilings now. I'm so looking forward to painting with the Matte after what I've read here. I figure that will be my reward after all the prep and priming fun. :-) Unless you can get Muralo Satin Flow. It's nicer. I'll ask my dealer if he has it. I have no issue with upgrading here if it gives better wear and is nicer to apply. Fresh Start acrylic primer is one of the best base coatings on the market. Excellent. I know my dealer stocks it in 5 gallon buckets. Thanks again for all your help!

Here are a few photos of my house where I photoshopped a render/mockup of what the white walls could look like. FYI, the dining room windows with the black wood blinds will be replaced with white cellular shades (the dark blinds make it so dark in there). I am also playing around with the idea of doing Kendall Charcoal on the window trim, which you can see in the office render. I like the baseboards being the same white as the walls, but not sure about the windows, although the dark trim around the windows on every window might be a bit much. Any thoughts? Do you think white walls and white-on-white works for my flooring, etc?

I have Classic Gray in my entry and hallway. My trim is SW High Reflective White. Classic Gray looks different depending on the time of day and the angle of the light, which I suppose is true of all colors. It is light and neutral. Here are some pictures from different angles and different times of day. Hallway is Classic Gray. Other wall is SW Magnetic Gray.

Pale Oak likes blue/greens, so I am going to suggest B.M. Super White (which also supports blue/green as a "go with") for wainscoting and all the trim. I am not a fan of painting wainscoting a color darker than the wall above, nor painting wainscoting a different color than the rest of the traditional trim, which you show in your photo. So what white is the wainscoting now?