Am I missing something as to why [Affiliate Partner] pays so much more for a much shorter duration call?

[Affiliate Partner] is pretty great at getting better deals on payouts initially than other affiliate networks. Where the true test comes in (with all pay per call affiliate offers) is in split testing the offers (for conversion rates). Once you have conversion rates (from your data), then you'll know which offer is more profitable, regardless of payout. You can run a split test with running two offers at once in the same campaign (using the round robin feature in Kallzu 2.0 call tracking software). See training video inside Kallzu 2.0 for setup of round robin.