I am in Suzhou with a dual entry, 6 month L-tourist visa. I arrived Feb. 3 and I am leaving June 30.

Do I have to leave mainland China on my 6 month dual entry tourist L-visa after 60 days and then return? It was issued Jan. 12 and I had to enter before July 12. I arrived in China Feb. 3 and I am now told by friends I have to leave after 60 days (end of March) and then come back. Also, do I have to just go through the controls in Hong Kong and turn around? Or, do I have to wait a certain number of hours for re-entry?