Due to many requests and running out of time to be able to repond to them - below is a link to the spreadsheet I used when we were making our decision whether or not to purchase DVC.
Please be advised that I do not guarantee in any way that the calculations are necessarily correct or that if they are, that they fit your particular situation. There are just too many variables for this to serve as a "one size fits all" analysis. Please use accordingly with that in mind.
Also, please do not use this as your only tool in making a decision as there are likely many other important considerations it does not cover.