As good as AdSense targeting is, what I’ve found over time is that there are certain words that act as POISON WORDS and can kill targeting on some site pages, even if those words appear nowhere on the pages, but simply are included in the global navigation of a site. It doesn’t matter if those happen to be higher priced advertising words - if they’re way off they just plain look silly and are a useless distraction.

There’s no doubt that it’s time to give a try at Section Targeting and if that doesn’t work for those pages, just not run AdSense on them at all.