Can we talk about the art for Infernal Calling in Xanathars showing a Horned Devil (CR11) being summoned despite the max possible CR for the spell being 10? #dnd my hopes are dashed

Infernal calling can summon a devil of CR 11 if you cast the spell with a 9th-level spell slot and possess that devil’s talisman. Take a look at the end of the spell’s description for more information. #DnD https://t.co/tjhfhKf8Oz

— Jeremy Crawford (@JeremyECrawford) April 9, 2018

Ok here is the problem at level 6 you can summon CR7, at level 7 you can summon a CR 8, at level 8 you can summon CR 9 and at Level 9 you can summon a CR10…..so tell me how you get a CR11 creature from level 9? The answer is in my previous tweet: the talisman.

— Jeremy Crawford (@JeremyECrawford) April 10, 2018