Its the point that interests me though, and I'll tell you why.
In 2003-2007 this board was full of these types of analysis. DVC was a great deal - resale prices were climbing. I did a lot of them myself (as I said, accountant and math geek), and I love them.
And a lot of people used these analysis to justify DVC. Sometimes, I could tell it was likely not a good idea for them, but unlike you, they didn't understand the difference between saving and saving. I've always been pretty financially conservative, so this has always bothered me here.
In 2009 many DVCers ended up selling at a loss. A few not only lost DVC, they lost their homes in the recession.
They believed that 1) prices would increase (we can always sell - in the recession, resale prices dropped like a rock.) 2) We will always go to Disney (in a recession without a job, they shouldn't have - although a few did a last trip, while losing their homes) 3) We can always rent (in 2009 not everyone managed to rent their points, there were more points to rent than people looking to rent).
One year of paying dues on points that you don't use throws all these calculations out the window. And usually at a time that you can least afford it.
I believe that if you acknowledge that this isn't likely to be any cheaper than what you are doing now, it removes one of those justification drivers that exist when people are sort of at the cusp of this decision. These discussions now scare the crap out of me. Because they sound so rationale, and they are. And they are very smart, and very smart people work the numbers. And numbers don't lie. The whole thing becomes very convincing. Especially to someone who doesn't REALLY follow the numbers - and frankly, most people have a difficult time with TVM. Except the numbers lie when the reality doesn't live up to the assumptions you made in your calculations. Finally, because I think that if your driving force is to save money (make trips cheaper), its a pretty high indication that you can't afford the risk (not absolute, some people are just frugal). If your driving force is to gain value for your money (either stay in a nicer place for the same amount of money, or spend more money to get something more - like a kitchen and washer and dryer) - that's a different deal. You and I are doing the second. And to me, that's a very important distinction.