Thanks Phillip for your explanation. I like the formula idea.

but I am no further ahead as it comes back to being unable
in distinguishing a different number for the same frequency.

This is further revealed when you have 3 of the same frequencies.
40 29
38 43
37 7
36 20
36 20 <---- should be 58
36 20 <---- should be 61
35 13
It is either predicated on the first or the last largest.
Is there anyway to break out from this situation?

With Thanks