BOClean Auto-Update CPU increase behaviour ?

After an auto-update the CPU usage of BOC421.EXE increases for about 30 seconds as though it is performing the startup scan again. This happens even when no update is downloaded (eg. no Internet connection).

To reproduce,

1) Change "Check for update every X hours, beginning" to 2 minutes so it will try to update 2 minutes after starting.
2) Shutdown BOClean and disconnect from Internet
3) Start BOClean and watch BOC421.EXE process CPU usage in Task Manager/Process Explorer

** CPU usage will stay high for about 30-40 seconds while startup scan is performed. After approx. 2 minutes, CPU usage will stay high again for about 30-40 seconds.

What's going on during the second CPU increase (startup scan ?), and should it be happening even though no new database is downloaded ?

Also, should it be performing a startup scan after a manual update when a new database is downloaded ?

BTW, CPU usage does not rise in a similar way after performing a manual update.