Anyone who has used TurboTax knows that the running refund/owe is not accurate until everything is entered. I’m mean seriously, how could it be? But it is a useful tool if you understand that. When adding an income, you can see hit it effects your current balance. When adding a deduction, again you can see how it changes the value.
Im sorry for your issue, but if you used that number to pay (or not pay) an amount for your extension and had not entered enough info (you do not have to enter everything, but enough to get a close number) to get a reasonable value, that is not the fault of the program. But rather a misunderstanding of how the program has worked for decades. However, given the complexity of your situation, I would recommend a licensed tax person to help calculate the amount to send with an extension.
As someone who has done taxes for decades, having it is a useful tool when explaining how income or deductions change the balance.
