one of my favorite places and ways to catch coho for years were the rocks in 12-30 ft of water off of Possession Point. I would troll a plug cut herring on a light weight actively trying to dunk and dive the bait on the lee side of those rocks on an outgoing ripping tide. the coho, that I think were headed to the bait house there, would sit behind those rocks to avoid that heavy tide. So I was fishing in prime rockfish habitat. big rocks and kelp beds with small baits. still I caught only a few rockfish (7 in my journal) in the 10 years I fished that. I did have a few good days (like 5) where I got some small ling that were back there but the ling seemed to only be around every so often.

why bring it up?

those and a handful of rockfish caught in the late 70's early 80's at the alki point buoy are the only rockfish I remember catching while salmon fishing. I didn't journal until the 90's. For most of my fishing life I did not troll at all, preferring to mooch, yet rock fish were almost never encountered. "one in every 28 trips" seems high to me. yet I think I would be on the high end of the spectrum due to my choice to almost always use bait, over lures, and avoid trolling.

thats my real world data.