Sorry Chris. We are referring to the amount of CO2 dissolved in the beer. If you dissolve 1 pint of CO2 in 1 pint of beer you have 1 volume, 1.2 pints in a pint is 1.2 volumes . . . . largers are generally served with 2.0 to 2.5 volumes of CO2 . . . . unless you are in the Czech republic when I've had it served with ale levels of carbonation (1.2-1.5 volumes)
80g of sugar in 23 litres of beer fermented at 20C will give you around 1.7 volumes of CO2, which is under the 'recommended' carbonation level for lagers at 2.0 to 2.5 volumes . . .personally I would say that was fine. . . . it will be more manageable for pouring.