On 31-Mar-2004, Jonathan Ball wrote:

Larger tanks have LESS increase in surface than the
increase in volume.

It is true that the volume increases faster than the surface area. So what?

Once you have a tank large enough to supply your hot water needs, any increase
in volume beyond that point will require an increase in surface area and more
heat loss. For maximum efficiency, you should use the largest single tank that
will supply your hot water needs.