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The extra seven days are {\em User Backup Time}.   The total user time will be 4168 hours.  This still allows each facility to calculate ``beam-availability'' according to their own definitions.  But at the same time it provides statistical data that can be compared to other facilities. \subsection{Discussion of Schedule Statistics}  A clear and dependable accounting of the user operation time is a prerequisite for a meaningful operation reliability evaluation of an accelerator.   To draw an extreme picture: if all beam outages are just declared to be shutdowns in retrospective then the beam is always 100\% available during user operation.   Which of course does not say anything about the reliability of the accelerator.  It is as well very important that only those times can be counted as User Time where the failures are recorded.  If failure modes within the extra time for the users are not analysed, then this time must not be accounted as User Time in the common operation metrics data.  At BESSY II the extra time given to the users is often provided with an unmanned control room during the night.  Therefore small failures can lead to long outages, if for example the beam is lost in the night and only accumulated again the next morning.  In those cases it makes sense to do a separate accounting for the extra time:  the failures are counted separately like it would be another operation mode.  This allows to evaluate the accelerator reliability for the scheduled time and the extra user time separately.