Originally Posted by
cblaisd
Maybe I should read more than 5 pages back

but I just talked to a MP CSR and was told the challenge also requires a $400 up front non-refundable payment.
that is the case for re-up challenges (so to speak) whereby you are trying to fast-track back to the status you just lost (eg, a former 1P drops to 2P and wants to take the challenge back to 1P).
for clarity, those coming in from other programs don't have to pay a fee for the UA status challenge, although the requirements have gone up since I matched this past summer.