Hello, I am a pilot based in japan.
The speed restriction mentioned in your post remain the same.
It is described in the Jeppsen airway manual "PACIFIC" => AIRTRAFFIC CONTROL=>STATE RULES AND PROCEDURES - FAR EAST=>JAPAN=>Speed Restrictions.
As for the request to exceed the speed limits, controllers are tend to approve such request if the traffic permits recently.
I hope this post might help.
regards,