I disagree. The receptacle under question is not covered by 210.52(A). How do we know? Because 210.52 (prior to sub paragraph A) says so. So I believe you can use a 15 amp circuit for this application.
All I read into that is that the recep at 6' cannot be counted as a required recep.
I noticed this a while ago and it begs a question, why is dining room mentioned in both the AFCI and SABC requirements. If you were to continue a kitchen countertop branch circuit down to cover the outlets in the dining rm. (very common) then it would have GFCI protection unless you wired it different to not include the dining room outlets as GFCI protected. At the same time are you protecting this with an AFCI/GFCI combo breaker or another alternative?
Reason I am asking is Oregon did not adopt the AFCI rule and I don't have to deal with this. Don't ask I just live here!!:grin:
The AFCI requirement for dining room receps does not prevent you from having them GFCI protected. It would be just as easy to extend a GFCI-protected SABC into the dining room, or split an SABC between the dining room and c'top and protect just the c'top receps.
There's no requirement in the NEC stating the dining cannot be GFCI protected, any more than if you wanted to protect every recep in a dwelling with a GFCI.