the 'Drv Pay' button opens the drive pay RECORD for THAT load, if one exists. remember : drv payroll normally calculates when load is marked EMPTY.
REMEMBER: if a load has not been put to EMPTY or you have not calculated driver pay using the 'Drv profit' button. then there is NO pay to show you.
if you have figured drive pay by pressing the 'Drv Profit' button or making a load EMPTY, it will display all the pay parameters for the load as seen here.