Another data point:
I posted previously in the thread (many many pages ago) about my $150-ish award ticket fee. I incurred it two days after I registered DL as my preferred airline. No credit appeared for weeks. After couple of back-and-forths via secure message, the CSR said the fee should've been credited (I didn't specifically refer to it as award ticket fee, as AMEX seems to want to retroactively exclude it from T&Cs via language in secure messages). The CSR said he'd issue a manual credit within 4-6 weeks
. I didn't argue, since I didn't really care WHEN, as long as I get it. Finally, today with my mid-June statement closing, the credit was applied.