I am getting a z visa, do I need round trip tickets?

Last year I went the China embassy in Chicago, and I was required to produced round trip airline tickets for a z visa. This is still not posted on the required documents site. Do I need round trip tickets to get my Z type this year? (I had to restart the process because I got a new job). I do not have the money to pay the high prices for the round trip ticket because I will need to stay beyond the 330 days that most sites will let you book. I do not want to get to the office with a one way ticket, only to be told I need a return ticket.