I have exactly the same problem. Battery Health was 100% when it arrived, 96% after the first charge cycle, and 92% after the second cycle. I am still undecided what to do about that.
Question to the original poster: Are you using the charger that came with the MBP (I think it is 60W), or did you use a more powerful charger (I think 80W) from the 15" models?
I'm not a technician but I doubt that after proper calibration the battery capacity should fluctuate by 10%...mine does fluctuate between 96-97%