What is Tandem repeat?
The DNA sequence "TATATATA" contains 4 repeats of the 2-mer "TA" and because these repeats are adjacent to each other, they are tandem repeats. The pattern of  nucleotides is repeated and the repetitions are next to each other.

This is what both the Wikipedia and the Simmons definitions are trying to communicate.  The statement you quote from Benson'a paper can be taken to mean the same thing (except for "approximate"), but might also be construed as saying the collection of all contiguous repeats is one tandem repeat, but that is not what was intended.

So, the oriC sequence has 4 tandem repeats of one kind (9-mers) and 3 tandem repeats of another pattern (13-mers).