Regardless of how accurate those figures are, SQL Server will only grab the memory it needs to start.  It'll take more and more as and when it needs it (for example to cache data or plans) until it reaches either the max server memory or the available memory on the computer.  It'll give back memory when requested by the operating system, subject to the value of min server memory.  That's a basic overview - there may be circumstances under which it will grab more memory than expected, especially in older versions.  I'm not sure whether or not Reporting Services behaves in the same way.

John