I hope you are asking two separate unrelated questions, because there's no point in doing cost segregation for properties held inside your self-directed solo 401k, save for some very rare exceptions.Some of the Bigger Pockets experts who operate reputable costs segregation companies are @Bernard Reisz, @Yonah Weiss and @Julio GonzalezSome of the Bigger Pockets experts who offer Solo 401k administrator services are @Dmitriy Fomichenko, again @Bernard Reisz and @Brian EastmanReach out to them and see if they can help.

This streamlines operations, reduces administrative burdens, and retains liability protection.

If you're not careful, the administrative requirements can trip you up—but when done right, the savings can be well worth the effort.For those of us scaling our portfolios or actively managing real estate deals, the conversation about structure isn’t just theoretical—it directly impacts how we protect our wealth and position ourselves for long-term growth.What I’ve found is that many investors don’t realize how critical their personal credit is in setting up these entities successfully and accessing the funding they need to operate and grow.

https://www.epa.gov/newsreleases/biden-harris-administration...

Loan administration is also a consideration although less important in this scenario. 

This is a post-closing penalty charged by the Escrow Administrator to extend the renovation period beyond the maximum renovation term of 180 days in the event renovation is not completed within agreed upon terms.

States and some cities get broad latitude on administration of the program.

However, it is possible that the new administration might bring 100% depreciation back. - Is it guaranteed?

On an annual basis, the administration is mostly meeting minutes, resolutions, and annual filing of your 990, most of which can be outsourced depending on your budget.

The more time you spend on administrative tasks coordinating with multiple service providers, the less time you get to spend on managing your properties, finding new potential investments and increasing your financial returns.Tax strategies and property insurance are two areas that are highly customizable because no two portfolios are identical.