Stub Payment Calculation Logic when proration method is 360 Days/Year

Summary:

We have an Equipment Lease using Proration Method = 360 Days/Year

We are adding new assets to the lease over time where the monthly payment of $1200 is pro-rated on a daily basis ($40/day).

What is the mathematical calculation Oracle is using to automatically derive the stub payment amount?

Content (please ensure you mask any confidential information):

When an asset starts on 2/26, FLA is calculating a $160 stub payment.

When an asset starts on 2/28, FLA is calculating a $0 stub payment.

When an asset starts on 3/31, FLA is calculating a $0 stub payment.

When an asset starts on 4/30, FLA is calculating a $0 stub payment.