Your question is rather complicated, since you don't actually live in Flint, but do have a Flint zip code.
You should contact the Flint Department of Revenue for clarification. I'm linking you to their income tax webpage. Telephone contact information is at the bottom of this page.
https://www.cityofflint.com/finance/income-tax/
*Please click the thumbs-up icon if this response was helpful.
**Please click "Mark As Best Answer" if your question has been resolved. Thank you.
*** I am NOT a tax expert. I am a seasoned TurboTax user, and volunteer to provide assistance to TT users. Nothing I post is to be considered TAX ADVICE; I bear no legal liability for responses.***