Fixed Asset & Profit and Loss question

Please help ?
How to rectify P&L mistake from last year?
Example, prior year 2017 purchased fixed asset (hire purchase for 3years) but did not capitalise and was treated as rental expense.
During the year 2018 fixed assets was recognised and my double entry:

1/1/2018
DR Fixed asset $3600
CR HP Creditor $3600
(to recognise the FA)

1/1/2018
DR HP Creditor $300 (3600/12 = $300/year)
CR Rental expenses $300 ? (prior year recognise $300 as rental expense)
or
CR Accu Depreciation $300
but what about depreciation expenses?

Jimmy.