Dues are misunderstood by almost everybody. Many seem to think that the dues you pay in January are for your Use Year points for that year. They are not. They are for the calendar year.
If you want to equate dues somehow to points, then it goes this way: If you have a June Use Year for example, and pay all your dues in January 2005, you did not pay for all your 2005 Use Year Points. Instead you paid for part of your 2004 Use Year points and part of your 2005 Use Year points.
When you first purchase, Disney prorates the 1st year's dues based on the remainder of the calendar year at that time. Then in January Disney charges for the next full 12 month calendar year. Again, if you want to equate it to points, think of it this way:
In 2004 you purchase an August Use Year. You pay 5/12th of the dues since they are prorated for Aug-Dec. In January you pay a full year's dues. You can think of it as 7/12ths is for the remainder of your 2004 points (which cover a vacation timeframe of Aug 2004 through July 2005) and 5/12 is for the beginning of your 2005 points. (The 2005 timeframe for an August Use Year is Aug 2005 - July 2006) You will wind up paying the remainder of the dues associated with those 2005 points, in January 2006.
If someone is paying their dues monthly, then when the contract sells all dues are paid in full and no refunds are required. Disney or the new buyer simply begins paying the monthly dues beginning with the next month.
If you pay 100% of your dues in January, you are paying for 12 months, regardless of when your Use Year is. If you sold the contract in July, you are responsible for 7/12ths of the annual dues, and therefore are entitled to a refund of 5/12ths of what you paid. That refund would have to come from the buyer or directly from Disney if they use ROFR. Any points you may have in any Use Year are totally irrelevant in regards to dues payments, but can be used to negotiate the purchase price based on who might get to use the points and therefore who should pay what proportion of dues. In the above example if someone sold an August contract where all 2004 points had been used and all 2005 points were available, and they paid 100% of the dues in January 2005, then the new owner should rightfully reimburse the seller 5/12th of the annual dues they paid. Some people wrongfully seem to think the seller is entitled to a refund of 100% of what they paid in January 2005 since they say that all the 2005 points are still available. What they conveniently forget is that the first year they paid dues, everything was prorated.