We placed our home in service in 2014 with 25% business use because 25% of the home was rented, and used 25% of the cost basis of the home as the amount reported on form 4562. In 2015, we placed an additional 25% of the home in service, so the total business use is now 50%.

Do we need to submit an additional form 4562 for the additional 25% percent increase in the cost basis, or do we just increase the depreciation amount on Sched E without submitting an additional 4562?