I didn't check last night, but every night before that it starts just a few seconds after 11 pm Mountain. I'm not running timed recordings but I assume it's still ending at 6:01 am the next morning.
I filed a complaint with the FCC last week through its online form. Have heard nothing sense and follow-ups are explicitly discouraged. That method seems to be the only way to file a complaint. The whole system seems designed to discourage contact with the public. But how else is the FCC staff to get complaints that they can act on? It's worse than Oakland city government, where the leaders always complain about budget cuts and constraints, but at least in experience the staff will return your phone calls and often are helpful. The FCC doesn't even list phone numbers. No wonder stations can violate technical parameters with apparent impunity. Where's Herbert Hoover when you need him?