said by Mr Matt: When I ran the numbers on the purchase of another RX hybrid I would have recovered the difference in cost if I kept the vehicle from 7 to 9 years if my wife was still driving the same route in South Florida.
You have put a lot of careful thought into all this.
What gets me are another sort that go overboard trying to analyze break-even points based on fuel economy, trying to 'prove' a vehicle like the RX hybrid a bad decision.
People routinely purchase less efficient larger engined versions of non-hybrid vehicles based on a desire for more power. This isn't wrong, it is just a choice. One can't calculate a number like fuel economy to 'justify' the decision.
In your case, you got better fuel economy + a significant power upgrade from your RX400h. Not having to refill the tank as often wins in my eyes too.