wrong number of active hosts?

Since about 8h I observe wrong, or unlogical number of "active host within past 7 days" published in the server status. There is also a severe difference between this number in the status report and in the associated grahical display of about -4000 to -5000 hosts or about -6.25%. As the number of new hosts is almost constant, these new host must be of extra ordinary high calculating power to over compensate for this loss, as the "results in progress", the "calculated floating point speed from results" and the "done work per day" - in the graphical display - are increasing constantly.