This is what I found last week and finally purchased points to get both DLCs, but they are still 1600ms points each.
Next week, from Feb. 19-25, the two most recent Elder Scrolls titles will be available at a discount. Oblivion, already a Platinum Hits title and currently priced at $14.99, will be on sale along with Skyrim, which is currently available on Games on Demand for $59.99. Microsoft has not yet announced the sale prices, but said they will vary by region.
Oblivion's Nights of the Nine add-on and Shivering Isles expansion will each be discounted by 50 percent to 200 Microsoft Points ($2.50) and 600 Microsoft Points ($7.50), respectively. And each ofSkyrim's three expansions will also be on sale at half price: Dawnguard (800 Microsoft Points, $10),Hearthfire (200 Microsoft Points) and Dragonborn (800 Microsoft Points).
This came from polygon.com and major nelson.