Decreased value almost certainly guaranteed. Unfortunate timing involved. We are seeing appraisal values decreasing, foreclosures significantly rising, lending practices tightening, and overall economic conditions that are not conducive to the most profitable selling; particularly in the luxury/upscale homes market. We are living the time worn cliche, "it is a Buyer's Market." Arbitrary Sellers should sit out. We are jammed with inventory, some of which is distressed in any price range. This is going to have only a negative impact on selling prices.
Real Estate values are themselves arbitrary to some degree. If what you have has the right appeal/value to the right person you might dodge the bullet but generally speaking expect less. As Dan mentioned, closer investigation needed to nail all the specifics into your deal. Glad to help if needed.

I would be willing to look into this futher if you will give me a little more information to work with email me at danproperties@mowisp.net