Buses time shedule Gansu from Xiahe to Songpan

During this summer, is it possible, by bus, to go from Xiahe in Gansu to Songpan in Sichuan, in one day ?
I saw these time shedules :
Xiahe – Langmusi 7:40 am Duration : 4 hours. Is it exact ?
Langmusi – Zoige (Ruo'ergai) At what time ? Duration : 1 hour.

Zoige (Ruo'ergai) – Songpan 6:30 am Duration : 6 hours
Do you know if there is a bus in the afternoon from Zoige(Ruo'ergai) to Songpan ?

Many thanks for your answer.