I was in the lounge 2 days ago. The guys making the sushi were handing it out on individual plates at 9:30 am. Top class tuna, it was excellent.
If freshly made sushi is important (it is..), then the guys making it in the JL F lounge don't release it until late afternoon. You can look at it being made as much as you like, but they won't put it out for consumption until the designated time.