I think you’re on the right track. My guess would be that they have a 3% tolerance (uncertainty, idk) with filling so they fill 600 ml but statistically it might be as much as 618. Putting 618 on the packaging lowers the price per liter a little, compared to 600.
This seems backwards from what a manufacturer would want to do. The concern with variances isn’t really having too much but having too little in the bottle. If you aimed to put exactly 600 in the bottle, you will sometimes end up below 600. It would make more sense to label it 600, aim for 618, and be confident that you’ll always fill it to at least the advertised 600.
Maybe they have one machine set up to fill the bottles. In one market they are required to deliver a safety margin of 3%. So they put 618 in a 600 bottle. In the other market there is no such requirement. So they write 618 on the bottle.
If by law they need to never be under the written volume, then writing 618 means they need to put 618 * 1.03 in the bottle to make sure they hit the 618ml written on the bottle.
In your example, they would write 600ml on the bottle and fill it with 618 ml to account for the machine tolerance.
618ml equates exactly to 600ml + 3% - maybe manufacturers add 3% on top because that’s the maximum allowable variance in quantities?
From a quick search, 412ml and 515ml both seem pretty common too.
I think you’re on the right track. My guess would be that they have a 3% tolerance (uncertainty, idk) with filling so they fill 600 ml but statistically it might be as much as 618. Putting 618 on the packaging lowers the price per liter a little, compared to 600.
This seems backwards from what a manufacturer would want to do. The concern with variances isn’t really having too much but having too little in the bottle. If you aimed to put exactly 600 in the bottle, you will sometimes end up below 600. It would make more sense to label it 600, aim for 618, and be confident that you’ll always fill it to at least the advertised 600.
That all depends on what they’re optimizing for. Underfilling is more profitable, but runs the risk of customer complaints and regulators stepping in.
Maybe they have one machine set up to fill the bottles. In one market they are required to deliver a safety margin of 3%. So they put 618 in a 600 bottle. In the other market there is no such requirement. So they write 618 on the bottle.
If by law they need to never be under the written volume, then writing 618 means they need to put 618 * 1.03 in the bottle to make sure they hit the 618ml written on the bottle.
In your example, they would write 600ml on the bottle and fill it with 618 ml to account for the machine tolerance.
This is pretty compelling. I vote “solved”.