Pivot Calculations

I was wondering what time periods were used for this site's pivot calculations for the ES. The open and close times. I can't get my pivots to match up with them.
Thanks

The "all sessions" times are used for the markets. This means that the open is the previous day at around 4:30pm ET and the high/low of the day might be made overnight. Most of the time, however, the high/low of the day is made during the RTH trading session and it is the average of these 2 figures and the close that calculate the classic pivot point so it is usually the same as the RTH pivot calculations.

Thanks