Allocation of Tax exempt interest from other states on NC Part year resident

[bjacobstax]

2021: Lived in NC from Jan-Aug, SC from Aug-Dec. NC State program has prefilled a number for non-NC tax-exempt interest supposedly taken from Federal Schedule B worksheet based on the entries I made indicating the State the interest came from. I can't figure out how they are getting this number. Is it computing a percentage? I did a spreadsheet and recorded all tax-exempt interest by date and state and sorted and computed just what I should need to add back in for NC. All Tax exempt interest I received between Jan-Aug from states other than NC and it's way more than what  Turbo Tax is prefilling. Can you tell me where that number is coming from? Looking at "data source" just says "Federal Schedule B, Interest Income Smart Worksheet, amounts coded as "E" type with a State ID other than "NC" But I can't find any Type "E" indicated nor the number they are using. How do I make sure this is correct?

[ErnieS0]

You can adjust the amount of taxable tax-exempt interest being taxed by North Carolina on the Part Yr/NR Wks. 

Go to 17 line Interest income from other states and enter the number from your spreadsheet in the column NC Source Income during NC resident (PY Resident).