Manufacturers really don't care too much about shipping costs (and the secondary CO2 burden) once the machine leaves their loading dock. Their concern is to make the machine as cheaply as possible for the features involved and maximize the margin.
That's probably also the reason why machines are cheap to buy online. If shipping was a constraint, buying at big stores would be cheaper.
Therefore, concrete can save some CO2 but probably not much cost. The cost of replacing faulty water tanks could be higher than the saved cost.