thanks @Mike9241 for your help and showing this examples and details.
This is complete paragraph from form 8990 IRS instructions. It seems like they are making a distinction of business interest income and interest income. Box 5 of K1 is listed as Interest income.
Either way amount is zero I think
Box 5 = 50
20a = 500
Box 5 - Box 20a = -450 or 0
There is no specific Business interest income box in 20s.
Is my assumption correct?
Business interest income. Business
interest income means the amount of
interest income includible in the taxpayer’s
gross income for the tax year, which is
properly allocable to a trade or business.
Business interest income does not include
investment income.
See C corporation business interest
expense and income, later.
Interest income that is allocable to an
excepted trade or business is not treated
as business interest income.
