its like this, when you fill a bottle you are trying to compress alot of shit in a little place, and it gets compressed and hotttttt, therefore harder to fill and will take forever, but if the filler freezes your bottle, when he hooks it up to the NOS refill thing, it will almost suck about 7 to 8 pounds into it and he only has to pump a couple pounds and its easier for him, but yes you can cram just a tad more into it