Yes, interest income can be included in both calculations. It is included in your overall taxable income calculations. And, Form 8960 applies a surcharge tax of 3.8% when you have certain net investment income and your modified AGI exceeds certain statutory thresholds.
You can read more about this tax and its history at the links below -
https://www.irs.gov/individuals/net-investment-income-tax
https://www.irs.gov/newsroom/questions-and-answers-on-the-net-investment-income-tax
