my apple watch shows inaccurate data about standing

Here is a definition of the stand ring;

This is a quote from Apple Support website;

The Stand ring shows hours in which you've stood and moved for at least a minute. Complete your daily Stand goal by standing up and moving around for at least 1 minute during 12 different hours in the day. Even if you stand all day, you still need to move around.

The minute that you stand and move around can be anytime from 1 minute after the hour until 1 minute before the next hour.

If you have stand reminders turned on then if you haven't stood yet in the current hour then the watch will remind you to stand at 50 minutes past the hour,this gives you 10 minutes in which to stand and move around before the next hour starts.

No I'm afraid 1 minute is written in stone and is not changeable.

What you can change is the number of hours per day that you have to stand for a minute in order to close your stand ring.