The total run time of one google script execution cannot exceed 6 minutes. If it takes more than 6 minutes the operation will be terminated without any notification. You can use "Generate a log of all automatic operations to a separate sheet" option to identify how long the script executes. In case you reach this limit you can try to split query/report into different spreadsheets.
You can only setup auto refresh process for 20 spreadsheets per google account.
Auto refresh process cannot be executed more often than one execution per hour.
When the exact execution time sets up, for example, 11am, it doesn't mean the execution process will start exactly at 11am. Based on Google scheduler's rules the execution time will be within 11:00am and 11:30am time frame.
