It seem really tricky to find the perfect ad replacement for the PSA adsense ads without violating both ends of the ToS' What have you've replaced your PSA ads with?
you dont need to replace it with anything else. PSAs are shown if your page/site is new and not indexed. some sites would still show PSA if it is not easy for google to crawl and index your site content to figure out the theme and which ads to serve. in this case, you can use "section targetting" (just google) which will resolve the issue