Subjugate Outsider Incantation

[Garnfellow]

The statblock for the incantation lists the target as "One outsider of up to CR 6 (see text)." The text notes that "If you call an outsider of CR 11 to CR 15, the DC for the incantation is increased by +4. If you call an outsider of CR 16 or higher, the DC for the incantation is increased by +8."

So what about outsiders of CR 7-10? Is it +2 to the DC of the incantation?