Motor vehicle Purchase with Finance and Trade in

Hi all,

We are purchasing a new Motor Vehicle with a trade in of old + Finance.

i would usually process this as a journal although the dealership requires a tax invoice for the sale.

So i need to change the process - the accountant agrees although isnt familiar with the system.

Entry as follows:

Generate a Tax Invoice for sale of asset.

Pay Invoice for sale of asset via Contra Account. 

Generate a purchase for the new Motor Vehicle

Pay Invoice purchase via Contra Account. 

Contra now has a balance to clear.

Generate Loan journal

CR - MV Finance

DR - Unexpired Interest

DR - Contra Balance (used to pay the trade in sale and new purchase)

This establishes the new loan and clears the contra account.

Set up the monthly re occuring payments as normal.

Is it right to use a contra account in this example? i need to clear the sale and purchase as this is not put through as journal.

Thank you!