@gloaming
Our baseline blood pressure is not the lowest that we get in a set of measurements. Scientific evidence available online - of which I am attaching a couple of documents - clearly indicates the necessity to average readings. Using the results of more than one reading allows the estimation of the variability in the blood pressure measurement which is very important. Variability depends on many factors some may be related to the instrument and others may be associated with the individual. You need to know that.

I take my blood pressure every week under the same conditions: after getting out of bed, before breakfast, sitting comfortably with hands and arms resting on the table, feet on the floor. I always put the cuff directly on my left arm. I take three measurements, and average their systolic and diastolic values, as well as the heart beat. Since the measurement conditions don't vary during the readings, I don't have to worry about the factors that you mentioned. The average of those three values corresponds to the blood pressure under a standard relaxed setting.

I record the readings in a spreadsheet, so I can tell you that your statement that the third reading of a series is the lowest was verified only 36% of the time for the systolic and 33% of the time for the diastolic in a set of 83 measurements that I took since December 3, 2023. Besides, the lowest systolic doesn't always coincide with the lowest diastolic: so what do you do when that happens? Do you pick the lowest systolic and diastolic values from different measurements?

Your system is not appropriate to provide guidance to you or your provider about your real heart condition. It's actually dangerous because it's totally biased to low blood pressure values.