Overtime for casual AiNs at Ramsay

I am a casual assistant in nursing working at a private hospital run by Ramsay. What pay rate is used to calculate my overtime?
Under the Ramsay Health Care Australia Pty Limited and NSW Nurses & Midwives’ Association and ANMF NSW Branch Enterprise Agreement 2018–2020, the overtime rates applicable to a casual employee will be the penalty rate applicable to a permanent employee holding the same position (i.e. no casual loading included in the calculation). However, Ramsay was required to provide an undertaking to the Fair Work Commission prior to the above agreement being approved that casual assistants in nursing entitled to overtime will be paid utilising their hourly rate with the casual loading included.