Island in the Sky: Planning site for our new home in Roosevelt Ridge, Gilpin County, Colorado

After we had the loft painted with a 'modern' flat paint, I quickly realized that this paint did NOT like to be washed off.  Spots, streaks etc just weren't coming off.  I began to think a semi-gloss or satin might have to be on the walls of the island in the sky.

But.. I started reading about a truly washable pain available in a matte finish.  I've seen some good reviews. I'd like to look into it for the house.

Benjamin Moore Aura

If this proves to be too expensive, I'd like to know what options are available to assure a flat but washable painted wall.