Hi Parti ,
In PCo Query if you choose current mode for tag retrieve query , due to time delay/ difference of tags in shop floor level will be getting the values across the timestamp.
Mean while you can try work around with below steps
1)select mode - tag aggregate query
2)In date range tab you can select the duration units as you need
3)In tag Aggregate query tab - select aggregates as min or max for the particular time line .
Else can be handled via transaction.
Regards,
Adhikesh