Stone Forest back to Kunming East Bus Station Schedule

Hi everybody...
could you please provide me the information until when the bus operates back to the Eastern Bus Station (time from to?) i would like to leave Shilin between 2 PM and 2:30 PM to catch the sleeper bus in the South bus Station at 19:00 to Yuanyang do you think thats possible (i calculated a taxi from Eastern to South Bus station approx. 30 min.?!)
Thanks a lot for your help.
Cheers Jasmin