Based on the readings I've done so far, there doesn't seem to be a well-defined, quantifiable method for interpreting bone markers. To me, the trend is my friend. The overall trend appears to be the most informative, especially when comparing your lab results to patterns observed in clinical studies. When starting a new or uncertain treatment pathway, it's ideal to have a baseline before initiation, and to monitor periodically to assess whether the therapy is effective. Admittedly, it can sometimes take persistence to convince a physician - but presenting clear reasoning can help (you could also ask pcp for lab order, my insurance doesn't mind who orders them). That said, during the process of prolia discontinuation, monitoring bone turnover markers is essential. This might be a good reference to start:
https://academic.oup.com/edrv/article/44/3/417/6889555
If you are comfortable sharing, what are your bone marker levels at this point in your therapy?