[V0latyle]

I'd like to point out that excessive crankcase vacuum generally won't cause excessive oil consumption, although it will accelerate wear in certain areas of the engine (such as cylinder walls) because it pulls the oil back into the crankcase.

It sounds like what you're experiencing is excessive pressure, likely from blowby.

The PCV valve fix should reduce oil consumption if anything.

 

[V0latyle]

Yes, except insofar as the excessive vacuum might be indicating excessive flow through the ventilation system, so that the ability of the system to separate the liquid and gas phases is overwhelmed. That's why it's important to have the right orifice installed.

What orifice where?