Roof Care and Maintenance suggestions. SEE Finally Update NEED HELP!

Chuck, your black blotches look totally different from what my roofs did. Mine got really fine checks in it and the pressure washing blew off what looked like white sand. Then I could see a little of the black layer under the top white layer but it sure wasn't anything like yours. My ex was a microbiologist, so... I would try a bleach solution on yours just to see if it's mildew or mold. If it is, I would want to kill it before recoating. Craig