Not that this really matters........
I have consistently been getting more 1st running volume than I should even though I have correct grain absorption and dead space variables. My 2nd runnings are always right on. Also, my volume markings on my Ss mash tun are off by about 0.25gal.??
Figured it out.
Turns out that I have been measuring my strike volume at room temperature, then heating it up, transferring it to the MT, and proceeding. Turns out I hadn't thought about the thermal expansion gain in volume which is probably near 0.25gal which pretty much corrects everything. So now I will heat first, then adjust strike volume.
Not that it matters because I just adjust sparse volume dependent on 1st runnings, but I am OCD. Academic I know.