Which … would be exactly what you expect, even though it’s likely inflated a bit - if I buy a house for $400k this year and sell it in ten for $500k and buy another one for $600k did I spend $600k overall or $1m? You could even argue for $500k.
None of the above unless you bought them outright with cash. These are more likely to be levered transaction, which means it depends on your interest rate and term, among other things.
You spent $1m on houses. You did not consume $1m worth of houses, nor did you spent $1m of your own money on houses if you used a loan. These are all subtly different metrics.
