As long as we are clarifying, compression as we measure it by mathematics assumes a tight cylinder at BDC. That gives us the number we all talk about, and manufacturers advertise. In reality the intake valve closes at some point after BDC and that lowers the effective compression. As the engine RPM increases, intake charge inertia will eventually overcome the charge rejection caused by the vertical movement of the piston while the intake valve is still open. With mild camshafts this point is hardly noticeable, but as the closure point is made later and later, the effect is the "cammed" engine, which suddenly seems to come alive at some distinct RPM. That point is not so much caused by overlap, but by the intake valve closure point. The D cam doesn't demonstrate it, but the R does.
I have built some domestic engines which had a cranking pressure of over 200 psi with an RV type cam and only 9.3:1 CR, and others with wilder cams and 10.5:1 CR that pulled only 150 psi. Variable valve timing is popular because it can allow things to happen which a fixed valve event cannot.