Pivot point calculations using Bhavcopy

Why are the OHLC values on daily and hourly charts different?

In the Above link you have Clearly mentioned that
" The exchange OHLC for the day on bhavcopy will be 100% accurate as it will be created using all the ticks that happened on the exchange."

Since you have the 100% accurate data why can’t you calculate Pivot points using Bhavcopy data instead of calculating Pivots using the live data that u received from exchange …

Bhavcopy will have only OHLC of previous day.