I've heard that the last 500 psi of tank air contains more cubic feet
than the 500 psi from, say, 2500 to 3000. This logically makes sense to
me but my question is whether anyone can quantify the difference. Is it
significant ? Anyone have a readily available table that illustrates
this ? If the difference is significant then maybe I can convince
myself to quit worrying about only getting a 2950 fill instead of a 3100
or better if it only means a couple more breaths.

Thanks in advance,