My oncologist also does the 27-29 and has since we started. I had surgery (high Ki67 and positive oncotype), chemo and radiation. Went onto anastrazole and now on exemestane. Mine went from 90, bounced around then to 69 after chemo. Stayed there for 4 months then started going up - 75 to 83 to 87 - at which point he ordered pet scan and brain imaging. Both negative and it suddenly dropped back to 69 after 6 months on ai. Has since dropped to 59 and has now been sitting there between 52 and 59 for almost a year. Some people apparently never go back to normal and they don’t know why. However he’ll continue to monitor every 3-6 months unless something changes drastically. So don’t over worry it. Your doctors still keeping an eye one it and there can be fluctuations that mean nothing.