Isaac, you're right. That could be a bigger savings. Say a special pioneer drove 10,000 miles out in service in a car that gets 25 mi/gal. In 2009 he would get $5,000 back from the WTS. In 2010, he would get $1,000, so the WTS saves $4,000. Note that some portion of these special pioneers are married couples-- of the few that I've known over the years, most have been married couples, and I think most of the kicked-out Bethelites are married couples.
To the extent that the married couples have worked together, that will reduce the impact of this new policy. For example, I can imagine a married couple driving 15,000 miles in service during the year. In 2009, the WTS would reimburse them $7,500. In 2010, their reimbursement would be $1,500, which is $5,000 less than 2009. But that works out to only $2,500 less per person.
It seems clear to me that this new policy will have a HUGE impact on the special pioneers. Under the old policy a special pioneer could almost double his/her "income" via the mileage. No doubt many/most/all special pioneers were using this mileage money to pay for essentials (rent, utilities, food). Must be tough to get the rug yanked from under you like that.
As a side note, does anyone know how many special pioneers are in the USA? It's been a while since I've seen a KM (and I think they may not even include all that info anymore).