You being a “partner” and then paying the “profit” to the builder makes no sense.

The new property has to perform enough better than what you have to pay the higher interest rate on the higher balance, AND ADDITIONAL profit just to payback the $65k you lost selling.

If you can focus more on that, then the bottom line profit you will be light years ahead of most flippers. 

Then sell and take the proration of tax free profit.

Your profit is the difference between your adjusted cost basis and your net sale.Adjusted cost basis is your cost of acquisition plus any capitalized improvements minus depreciation.It is very possible that you could sell a property you have refinanced and generate no cash at the sale but still have a big tax bill because you sell it for more than you purchased it for.

Cause you don't want to tell the original seller how much profit you're making?

I currently own my home I live in (not paid off) and have one rental property that’s fully paid off thats profiting about 1k a month.

Engage with property managers for insights on rents, expenses, or off-market opportunities, and request financial documents like rent rolls and profit/loss statements from sellers’ agents as part of due diligence.

Flipping houses in the current real estate climate with higher interest rates impacting long-term rentals offers exciting possibilities.Given the strong seller's market in the Dallas-Fort Worth metroplex, including Garland, selling your flipped property could yield a quick turnaround and potentially higher profits.

I guess we could maybe have the builder agree to the cost of the build and if we sell for more or less then the profits would go up and down based upon the selling price.