Weekly per diem for o/o?

Hey so I'm a new owner operator and I know that we can pay ourselves per diem.
My question is can I do it as a weekly deduction? As opposed to deduction all of it at tax filing time?

Example: my net before tax is $2000. I take out $64/day x 5 days= $320.
Then tax myself on $1680 for that week.

Pretty sure I can do that as long as I keep a record of it yes?
Thanks