Just a note, have you checked the coding for any caching? There's a caching function in ASP.NET that looks something like HttpContext.Current.Application.Item(key) = objValue that caches the SQL query result. Usually SQL Server doesn't return the same result when we query it.
And to clear the buffer cache, you can use DBCC DROPCLEANBUFFERS. This might slow some queries down since cache is empty. You can check you coding and try clearing your SQL buffer and try again to see if it's SQL cache.