Valve Clearance on Larger Camshaft and Flat Top Pistons
If the he your refering to is Billy Godbold and the subject Billy is talking about is the section titled "checking undeflected and deflected lift" then I think he is refering to the amount of deflection remaining after you stop turning the crank. I'm not sure how you could measure it while turning the crank by hand. refer to image 2-33 page 37 the column labeled "stock deflection".