When will the 3 day unlimited ride of Hong Kong Airport Express Travel pass start?

Let say I am going to use my AE on June 4 (Airport to Kowloon + Free Shuttle bus to hotel), then I will start to use my 3day unlimited on June 6 at 8am. It will expire on June 9 at 8am? Or by the time I use my AE on June 4, it starts counting my 3-day usage? Thank you