Trying to calculate reducing balance method for depreciation on a vehicle.

Opening Balance / Cost Price = 24870

Accumulated Depreciation = 2632

At the end of the accounting period (one month) I need to depreciate the asset

Depreciation rate = 20%

Mu confusion is - the accumulated depreciation is not for a year, indicating the asset was bought through out the previous financial year.

Is the calculation

(24870-2632) x 20% and then divide by 12 to get the monlthy expense ?