So, the value is higher than the $18,000. The balance will be depreciated over 5 years with regular depreciation.
From IRS Form 4562 instructions:
For qualified property (defined below) placed in service during the tax year, you may be able to take an additional special depreciation allowance. The special depreciation allowance applies only for the first year the property is placed in service. The allowance is an additional deduction you can take after any section 179 expense deduction and before you figure regular depreciation under the modified accelerated cost recovery system (MACRS).
