Optimize this code

[d00_ape]

I have a function that very often are called. Any tip on how to optimize this code:

private static double CalculateDifferance(object from, object to)
{
   if (typeof(int) == from.GetType())
   {
        return (int)to - (int)from;
   }
   else if (typeof(DateTime) == from.GetType())
   {
        return ((DateTime)to - (DateTime)from).TotalSeconds;
   }
   else if(typeof(double) == from.GetType())
   {
       return (double)to - (double)from;
   }
   return double.NaN;
}