Fear of an audit stops a lot of investors from taking depreciation the law plainly allows. The grounded answer: cost segregation is an accepted application of MACRS under IRS Publication 946, the IRS publishes an entire Cost Segregation Audit Techniques Guide telling its examiners how to review studies, and nothing in that guide or any IRS release says that doing a study flags a return. Anyone quoting a specific audit rate for cost segregation returns is inventing a number; the IRS does not publish one.
What the Audit Techniques Guide actually signals
The guide's existence means the IRS sees enough studies to want consistent exam standards. Read it as a quality bar rather than a threat. It tells examiners to check whether the study reconciles to total basis, whether classifications have legal support, whether the preparer was qualified, and whether cost estimates trace to real records. A study that meets that bar is routine. The returns that draw adjustments are the ones built on aggressive reclassification percentages with no engineering substance behind them.
Form 3115 is not a confession
A look-back study rides on Form 3115, and some investors worry that filing it invites scrutiny. Under the automatic change procedures described in the Form 3115 instructions, changing from an impermissible or less favorable depreciation method to a permissible one is a consent-granted change: you file the form with your return and a copy to the IRS, and the section 481(a) catch-up lands in the year of change. It is one of the most commonly filed accounting method changes and is processed administratively, not routed to an audit queue.
Where the real risk lives
Consider a $1,500,000 office building where a promoter-style report claims 45% of basis as 5-year property with no asset detail, no inspection evidence, and no reconciliation. If that return is examined for any reason, the examiner applies the Audit Techniques Guide, the study cannot support its numbers, and the reclassified depreciation is adjusted away with potential accuracy-related penalties under section 6662. The same building with a documented engineering study showing a 22% reclassification survives the same exam. The study's quality, not its existence, is the variable.
Practical risk management
Keep the full report, closing statement, renovation invoices, and inspection evidence together for as long as you own the property plus the open statute years. Make sure the return matches the report exactly, since mismatches between the study and Form 4562 are self-inflicted wounds. Amadae's role sits on this compliance side: it screens properties before anyone pays for a study, models the benefit honestly, prepares the Form 3115 and section 481(a) math for look-backs, and files returns that tie to the engineering report line for line. Amadae does not perform the studies themselves, and a screening estimate is never a substitute for one on a filed return.