system.web.caching

I am using System.Web.Caching.Cache in an assembly used by my website. I have set some key expiration (absolute expiration) to be 10 seconds (just for debugging). I have also set a callback upon key removal. The problem is that I see that the cache is getting refreshed after something like 20 seconds and not 10. I am using HttpRuntime.Cache for this. Any suggestion for why is that happening ? I would like to show a code sample, which can shed more light: public void OnUpdate(string key , CacheItemUpdateReason reason , out object expensiveObject , out CacheDependency dependency , out DateTime

The examples for Cache.Add uses DateTime.Now.Add to compute the expiration, i.e. it passes: DateTime.Now.AddSeconds(60) as the value of the absoluteExpiration parameter. I'd have thought that computing it relative to DateTime.UtcNow would be more correct [as there is no ambiguity if Daylight Savings Time starts in the intervening time between now and the expiration point]. Before the introduction of DateTimeKind , I'd have guessed that there's some ugly hacks in the cache management to make it do something appropriate if the time was not a UTC time. In .NET 2.0 and later, I'm guessing that it