That was an important part of it. Measuring runoff coming out immediately isn't very meaningful. It didn't have time for the soil to impart it's pH upon the liquid. The theory of that method is that the liquid sit in the soil and equalize for an hour. Then, displace only a measurable amount (i.e., don't dilute the equalized liquid any more than you have to to get a measurable amount.).
Regarding your runoff PPMs. If you took the soil sample from the top, it may not have much salt. It may have collected further down.
For me, 2000ppm is where I feed with more runoff and/or reduced strength. I like to keep it around 1800ppm (0.5 scale) in flower. If it goes to 2200, I feed 1/4 strength or water only (50% runoff, or more). If it reaches 2500 I'll see the plant falling apart.
