You can have a gun that is on the face and have adequate bite , that is lose in the action when the forend is off or when the gun is opened . Alternatively you can have a gun that is tight in the action but off face or have no bite .The again you get some guns that are just sloppy ,off face and have no bite at all .
There is no one size fits all answer , it is a matter of degrees of what is acceptable and when it need to be rejointed .
Prepping a gun for proof in the UK, it has to be tight in the action , on the face and have more than normal bite with no forend on .
When I was an apprentice working on new guns I was taught that to be correct the weight of the barrel should be enough to open the gun [drop gently ]when the lever was opened so it was a combination of barrel tightness in the action and bearing of the forend .
