Webster Products, Inc., adopted the dollar-value LIFO method of determining inventory costs for financial and income tax reporting on January 1, 2021. Webster continues to use the FIFO method for internal decisionmaking purposes. Webster’s FIFO inventories at December 31, 2021, 2022, and 2023, were $300,000, $412,500, and $585,000, respectively. Internally generated cost indexes are used to convert FIFO inventory amounts to dollar-value LIFO amounts. Webster estimated these indexes as follows: 

2021................1.00 

2022.................1.25 

2023.................1.50 

Required: 

1. Determine Webster’s dollar-value LIFO inventory at December 31, 2022 and 2023. 

2. Will Webster account for the change (a) retrospectively or (b) prospectively?