On August 1, 2015, a machine with a cost of $420,000 was traded-in for a new machine with a cost of $650,000. The seller agreed to receive $285,000 in cash and the old machine. The machine is depreciated using the straight-line method with a 15,000 residual value and a useful life of 5 years. The accumulated depreciation has a total balance of $324,000 on December 31, 2014.

Prepare journal entries and show calculation to:

1. Record depreciation for 2015 up to the date of disposal.
2. Record the trade-in transaction.

Assume the company changed the depreciation method to the Double declining one, prepare the journal entries and show calculation to:

3. Record depreciation for 2015 up to the date of disposal.
4. Record the trade-in transaction.

5. Which method should the company adopt if it wants to report high NI in 2012 and 2013?