Holley Power Valve Experimentation

Can a leak tester apply vacuum? I have one and I don't even know. lol
Just discovering it all. Using a specific vacuum on the tool with a valve in it should tell the tale I’d think. Maybe someone here has more knowledge about it and if you can get accurate results at various vacuum numbers? By the looks of it I assume you decrease the vacuum below the PV value and it should open?

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