MACRS STL30B -- MACRS: Straight-Line Mid-Month Convention - 30% Bonus For 36 months

MACRS STL30B --MACRS: Straight-Line Mid-Month Convention - 30% Bonus

This is a MId month convention. But this is present for 27.5 years and not 36 months.

If we want to use  MACRS STL30B --MACRS: Straight-Line Mid-Month Convention - 30% Bonus for 3 years, then how can we use this? Oracle is suessgting using Mid month convention. But while doing mid month convention, we have to create a new Depreciation method with 24 periods (right now we have it for 12 periods). While defining the depreciate method, we need to define the rates. How can we get the rates? Oracle is asking to get it from Business as it is not available, but business is saying that this is a common practice in US and it should