Indiana Department of Revenue Reviewing My 2024 Schedule C - Documentation Required by February 27, 2025

Just checked my USPS informed delivery and saw an IRS letter is coming, but it's actually from the Indiana Department of Revenue. They sent me a letter dated January 29, 2025 saying they're reviewing my 2024 Indiana individual income tax return. I'm getting super nervous about this! The letter states: "The Indiana Department of Revenue is reviewing your 2024 Indiana individual income tax return. To complete this review, provide copies of all the supporting documentation below regarding your Federal Schedule C by February 27, 2025." They're asking for: - Description of my business(es) including start date - Documentation supporting my three largest business expense categories - Documentation supporting all my business income (Federal Schedule C, Part I, line 1) - My original Federal (1040) return(s) and all supporting schedules filed with the IRS - All original and amended income statements (1099 MISC, NEC, R, K), K-1, and/or W-2 or W-2G forms The letter specifically mentions that they won't accept Excel spreadsheets or QuickBooks reports as sole proof of income or expenses. They want actual proof like paid invoices/receipts and/or canceled checks for income, and canceled checks or bank statements for expenses. They're warning that if I don't provide documentation by February 27, 2025, my "return will be adjusted to verifiable income" which they say will "likely result in a reduced refund or a bill." Even worse, they say "Future tax returns will be placed on hold for compliance review and you may not be notified by mail." There are several ways to submit documents: - Online via INTIME (intime.dor.in.gov) using the Letter ID - Email to DORITCInfo@dor.in.gov - There's also a note that documents "submitted online using the unique Letter ID printed in the upper right-hand corner will be applied to your account within 24 hours" I thought my return was pretty straightforward but I'm really worried now. Is this a full audit? Has anyone dealt with this kind of state review before? How extensive does my documentation need to be?