The Behr One Coat Coverage Guarantee states that if any of their 1,000 colors are applied, it will hide or cover the previous color in one coat.
The Behr one coat coverage guarantee only has a few stipulations.
First, you will need to prime any bare surfaces or surfaces with tannins and water stains.
Secondly, exterior surfaces should get two coats, regardless of coverage issues, for maximum protection.
Finally, you have to use Behr Dynasty paint or Marquee.
These stipulations are not a big ask.