Calculate STL Depreciation with Mid-Month Prorate Convention

Hi,

I have the below requirement for calculating depreciation mid-month using STL method.

1. Regardless of the date placed in service (before Jan 16 or after), the asset in its first month of service should be depreciated only for half a month.
2. Regardless of the date retired (before 16^th Jan or after), the asset in its last month of service should be depreciation only for half a month.

For instance, if the asset was added in 5th January of that year, we want system to only calculate half a month of depreciation for that asset in the first month of its life - same is true if the asset was added on 31st Jan. We also require the same to happen in the month it retires - only half a month depreciation.