Are closing costs deductible on a 40-year DSCR mortgage (purchase and refi)

[Dana Powell]

Greetings, when researching online, i came across a nugget that typically deductible closing costs can only be deductible on mortgages that are 30 years or less, but I can no longer find that web page!  If there is such a rule, does it pertain to rental property or just to primary home mortgages?

Secondly, since DSCR loans are considered business loans and not conventional loans, can closing costs that are typically deductible for conventional loans be deducted for DSCR loans?

In addition, am I correct in assuming that, regardless of whether a loan is DSCR or conventional, an investor can add the closing costs that are typically added to the cost-basis of a rental property? Thanks in advance!