Question on Golomb rulers

[David Wilson]

A003022(n) gives the length of a minimal Golomb ruler with n marks.  As such, it would be
the smallest a(n) such that there is a set of integers from 0 to a(n) with the property that
the absolute differences of pairs of distinct elements are all distinct.

Yet we have the comment

%C A003022 a(n) is the least integer such that there is an n-element set of integers between 0 and
a(n), the sums of pairs (of not necessarily distinct elements) of which are distinct.

In this case, we are not talking about absolute differences of pairs of distinct elements,
but sums of pairs of not-necessarily-distinct elements.  At first I thought this was an
error, but it seems that the sums are also distinct for minimal Golomb rulers.  Is there
something simple I am missing here?