Office swipe in and swipe out timings.

I normally stay 2 hours in office and go home and work. In 2office the range would be 0-3 hours.

But instead of staying for 2 hours sometimes can I just leave in 20 or 30 minutes and still come under 0-3 hours bracket

My manager said atleast maintain 3 plus hours which I will do it and come under the bracket 3-5 hours.