Depreciation Calculation when asset life in Web ADI file differs from life in Asset Catgeory

Dear all

We are on Oracle Release 12.1.2

Consider example of asset ABCD belonging to category Equipment, asset life as per asset category is 42 Years 0 Months

We loaded asset through Web ADI and mentioned asset life in Web ADI file as 15 Years 6 Months

System has not considered 15 Years 6 Months when asset was posted through Mass Additions, asset life has been populated as 42 Years 0 Months, also depreciation has been calculated based on 42 Years 0 Months

Our question is why Oracle Assets does not consider asset life given in Web ADI when depreciation method of 15 Years 6 Months is available, why it considered only life as per asset category