The loan on this house is $1,200,000.I moved in to my new primary residence by the end of the month.Starting July, my original primary residence was available as a rental and was being shown to prospective tenants.My new tenants signed a lease that began a couple weeks after showing, in July.To calculate my primary residence mortgage interest deductions, i'm using the following formula:650,000 / 2 = $325000 loan from January to June1,200,000 / 2 = $600,000 loan from July to December$750,000 limit / (600,000+325000 total loan value)  = 0.81 multiplier(0.81 * $X first house interest) + (0.81 * $Y second house) = total interest payed i can deduct from my primary residencedoes this look correct?

A goal is nice to set but the path too it is where I find the fun.

Recently, I conducted a cost segregation study on the property shortly after converting to a STR (converted June 1 2024), and I want to ensure I file my taxes correctly and legally given this change in circumstances.

I'm correct on this? 

Then level the floor - really shouldn't need more supports after the first if they were installed correctly.

Happy to discuss this further on what might make the most sense for your end goal.If you are renting right now and starting your path in real estate investing, as said above, I really do like the house hacking strategy for your situation.

correct and correct .... it's just the best what software can do.

Michael, you are absolutely correct. 

Two years is a long time for rehab, did I read correctly?  

Seller financing can be a valuable tool when used correctly, but its effectiveness depends on how it's structured and implemented.