[Retric]

An oxygen tank where you can safely add more oxygen by increasing the pressure is not considered full. The percentage of how empty a container is can be considered 1 -(amount of stuff in it) / (maximum stuff possible).

[mcnamaratw]

I think possibly you've defined "full" two different ways. Is it maximum safe pressure or maximum stuff possible?

[Retric]

I don’t see the contradiction, Space unlike a gas tank is not going to fail.