Believe the frenchman. I remember guys coming from Allisons to the Arriel and doing 2 minute rundowns. Longer on the Arriel is not good for it. The temperature in the bearings initially goes down but after 30 secs it goes all over the place. The problem is low oil flow at idle. In fact if you do idle an Arriel it is better to run it back to "Flight" for a period prior to shutting down. Operate IAW the RFM, simple.