Williams$-$Santana Incorporated is a manufacturer of high$-$tech industrial parts that was started in $2012$ by two talented engineers with little business training. In $2024,$ the company was acquired by one of its major customers. As part of an internal audit, the following facts were discovered. The audit occurred during $2024$ before any adjusting entries or closing entries were prepared.

a$.$ A five$-$year casualty insurance policy was purchased at the beginning of $2022$ for $$34,500.$ The full amount was debited to insurance expense at the time.

b$.$ Effective January $1,2024,$ the company changed the salvage value used in calculating depreciation for its office building. The building cost $$616,000$ on December $29,2013,$ and has been depreciated on a straight$-$line basis assuming a useful life of $40$ years and a salvage value of $$120,000.$ Declining real estate values in the area indicate that the salvage value will be no more than $$30,000.$

c$.$ On December $31,2023,$ merchandise inventory was overstated by $$24,500$ due to a mistake in the physical inventory count using the periodic inventory system.

d$.$ The company changed inventory cost methods to FIFO from LIFO at the end of $2024$ for both financial statement and income tax purposes. The change will cause a $$955,000$ increase in the beginning inventory on January $1,2025.$

e$.$ At the end of $2023,$ the company failed to accrue $$15,400$ of sales commissions earned by employees during $2023.$ The expense was recorded when the commissions were paid in early $2024.$

f$.$ At the beginning of $2022,$ the company purchased a machine at a cost of $$710,000.$ Its usefiharife was estimated to be $10$ years with no salvage value. The machine has been depreciated by the double$-$declining balance method. Its book value on December $31,2023,$ was $$454,400.$ On January $1,2024,$ the company changed to the straight$-$line method.

g$.$ Warranty expense is determined each year as $1\%$ of sales. Actual payment experience of recent years indicates that $0\mathrm{.}70\%$ is a better indication of the actual cost. Management effects the change in $2024.$ Credit sales for $2024$ are $$3,900,000$; in $2023$ they were $$3,600,000$

Required:

For each situation:

Identify whether it represents an accounting change or an error. If an accounting change, identify the type of change. For accounting errors, choose "Not applicable".

Prepare any journal entry necessary as a direct result of the change or error correction, as well as any adjusting entry for $2024$ related to the situation described. $($Ignore tax effects.$)$