But effects s1/0.1 as well:

R7#sh run int s 1/0
Building configuration...

Current configuration : 87 bytes
!
interface Serial1/0
 no ip address
 encapsulation frame-relay
 priority-group 1
!
priority-list 1 protocol ip high tcp telnet
priority-list 1 protocol ip low tcp www
priority-list 1 default medium
!