...and in that case, you don't really have to use it unless theThe AFD says “CLEARANCE DELIVERY PHONE: For CD ctc Washington ARTCC at
703-771-3587.”
Are you sure your downloads are up to date? If so, maybe a problem with Avare?
"CLNC DEL 124.85"
[there are a number of nontowered airports with CD frequencies which also have the phone number, probably because there are times the frequency has interference, but that's just a guess)