A good example is KHJ in Los Angeles, which only played three Brasil '66 singles. "The Look of Love" peaked at #2. So did "Fool on the Hill". "Scarborough Fair" only made #10. But beyond the peak number is this story---it took two weeks to move from hitbound to #25. The next week, #10. Then #12, then #24, then gone."Scarborough Fair" was played pretty frequently on the MOR station that I listened to. It seemed to me like a solid followup to "Fool On The Hill", but it wasn't all that popular on the bog Top 40 stations, as I recall.
Now, KHJ was a quick on-quick off station in those days. Seven weeks on the chart for a big record was about it. Six was more common. "Hey Jude" set some kind of record for charting for 11 weeks. But four---that's short. And it suggests it might not have really been a #10 or #12 record.
KHJ gave itself a lot of latitude by putting this language at the bottom of its weekly chart: "The listing of records herein is the opinion of KHJ based on its survey of record sales, listener requests and KHJ's judgement of the record's appeal. "