Asset Depreciation Forecast - custom function

Hi folks,

I am relatively new to Power Query and trying to simulate straightline depreciation for my assets (50k assets) in Excel. Since the dataset is big and assets are added every month I am unsure how to enable user droping forecasted depreciation value per month to their power pivot or how to build visualisation (line chart for future months). What would be a clever way around this please:

custom (universal) function
variable
measure
custom column/query step
new blank query

come to mind. Monthly depreciation is calculated as acquisition value ('**bleep**.acq.value' field) divided by useful life ('Life' field contains useful life in 'Years/Months' format). Depreciation runs only up to the depreciation end date which should be calculated as Start date ('Depre Start Date') plus useful life ('Life' field= useful life in 'Years/Months' format). 'Asset' number is not a unique number, it is unique in combination with 'Sub-number'. I believe below two tables should suffice to build a dynamic monthly depreciation forecast per asset, function or field which may be then used in power pivot and visualisations. Date table contains dates from 1/1/2020 till 31/12/2040.

Thank you.