Here is what I did - it is very similar to the one above.
Total Purchase Price divided by number of years in my contract = price per year.
Price per year divided by number of points in contract = Price per point per year.
Price per point + Maintenance Fee (per point) = Total Cost involved in DVC point.
I consider the loss of interest to be offset by the inflation factors in all hotel accomadation - so I do not try to factor that in, but you can if you want. I just rounded up to the nearest $ to help offset this economical cost. My "cost" is around $5.
Now the value of the points is based on "what the market will bear". This calculation is more complex and I will not try to recreate one for you. It seems to be a concensus on this board that the rental value of a point is around $10.