I have a car that reaches the bottom of the gas gauge and turns on an idiot light when the tank is still 1/4 full.
I carried gas and ran out. I found that if I set the trip meter when the idiot light came on, I had 80 miles to get to a gas station.
Today's load data is like that gas gauge and has to be worked around to get at the truth.
I am finding that I have to make assumptions about the ratio of change in pressure to change in powder [greater than 2 for fast powders, less for slower] and compensate for the wimpy over all length they tested at, and I have to raise the pressure on 9mm from 35k to 41k to get +P+. I have raise the pressure on 38 specials from 18.5k to 35k to get +P++++++.