Can anyone tell me what I am doing incorrectly?

320,000/40,000= 8 actual overhead cost divided by the actual units produced minus
335,000/45,100= 7.4279379 budgeted overhead cost divided by the standard units allowed (55,000x82%)
_________________________
= 0.5720621 predetermined total overhead rate?
x 40,000 actual units produced
________________________
= 22,882 total overhead variance





58,000/40,000= 1.45 fixed overhead cost divided by the actual units produced minus
58,000/45,100= 1.286031 fixed overhead cost divided by the standard units allowed
_____________________
= 0.163969 predetermined fixed overhead rate?
x 40,000 actual units produced
_______________________
= 6559 volume variance



The controllable variance should then be $16,323, but it's being marked incorrectly.

Thanks