It opens at 0500 and closes at 0830, and re-opens at 1400, closing at 2230 - the website is correct there. These times apply all year round. The new timings you refer to are likely what they do when there are delayed flights yet to take off, and some passengers on VS/DL operated services in the Clubhouse: they will keep the Clubhouse open, but they won't admit new passengers. I think they stop admitting about half an hour before closing, anyway, but that does vary depending on the outlook.