Per Statement of Financial Accounting Standards No. 34
“13. The amount capitalized in an accounting period shall be determined by applying an interest rate(s) (“the capitalization rate”) to the average amount of accumulated expenditures for the asset during the period. The capitalization rates used in an accounting period shall be based on the rates applicable to borrowings outstanding during the period. If an enterprise's financing plans associate a specific new borrowing with a qualifying asset, the enterprise may use the rate on that borrowing as the capitalization rate to be applied to that portion of the average accumulated expenditures for the asset that does not exceed the amount of that borrowing. If average accumulated expenditures for the asset exceed the amounts of specific new borrowings associated with the asset, the capitalization rate to be applied to such excess shall be a weighted average of the rates applicable to other borrowings of the enterprise.”
In this problem the average accumulated expenditures ($625,000) for the asset exceeded the amount of the specific new borrowing associated with the asset ($500,000 @ 12%) so you have to use the weighted average of the rates applicable to other borrowings (10% since there was only one other borrowing). The way I figured the problem may seem simplistic but it is GAAP because I used 10% for the capitalization rate. I think the fact that we got the same answer is a coincidence, I worked the problem again, but changed a few facts, using my method and your method. If you change the second payment to $900,000 and the interest on the other borrowing to 8%. The answers are not the same.
My method:
200,000 X 12 / 12 = 200,000 X .08 = 16,000
300,000 X 12 / 12 = 300,000 X .08 = 24,000
600,000 X 8 / 12 = 400,000 X .08 = 32,000
300,000 X 1 / 12 = 25,000 X.08 = 25,000
Total Capitalized Interest = $74,000
Your method:
200,000 X 12 / 12 = 200,000
900,000 X 8 / 12 = 600,000
300,000 X 1 / 12 = 25,000
Average Expenditures = 825,000
500,000 X .12 = 60,000
325,000 X .08 = 26,000
Total Capitalized Interest = $86,000
If anyone knows of another FAS that supersedes FAS 34 please let me know.