TOPIC: Which contract type is preferred below and why?

I have seen many questions where:
customer wants them to be preferred customer.
Which contract type is preferred:CPIF or CPAF ?

I always feel it should be CPIF.... but answer key says CPAF.

Can anyone justify?

Thanks
Puneet

Let's head to DAU to read the benefits of both: As such, a CPIF contract would be more beneficial, in theory, than a CPAF contract when the work to be performed is such that it is both feasible and effective to devise predetermined objective incentive targets applicable to cost, technical performance, or schedule. Look at what they write at dap.dau.mil/aap/pages/qdetails.aspx?cgiS...&cgiQuestionID=19994 . If the US government picks CPIF it's more beneficial to the contractor to go the other way, Because Award-fee determinations are subject to the Contract Disputes Act.
Best Wishes
jfw