Thanks Tower Guy. My conclusions were based on personal experience, but I thought there was something the OP may have overlooked.

I have 2 channel 12's within 100 miles here. The one 65 miles away with 23kw is 99% reliable even with some minor terrain obstructions. The 30kw channel 12 100 miles away (no terrain) is a rare catch, & never seems to affect the closer channel 12.