How does the PCM calculated desired idle airflow?

PID-controller corrections aside, how does it do this? I removed the factory PCV system from my car, which I believe allowed some intake air to bypass the throttle body under intake manifold vacuum. I'm unsure of the proper way of correcting for this loss of airflow.

Some people talk about the Base Running Airflow tables as telling it how much airflow to command, but others start idle tuning with Airflow Final Minimum zeroed out.

Does it use torque and friction models to estimate some equilibrium airflow? I'm not seeing a friction model like Chrysler hemi PCMs have.

Thanks.