I have a worker who gets $10 daily for a job, but he's got to be there
promtly @7:30am. For each 5 minutes late, $1.00 is docked.

I'd like to be able to enter into the cell 7:33am and this will bring up
$9.00. 7:37am 8.00 and so on.

Any help for setting this up would really be appreciated.

Thanks all