tak se asi jedna o jinou implementaci crontabu
na mem stroji se to chova presne podle poznamky z manovych stranek:
Note: The day of a command's execution can be specified by two fields -- day of month, and day of week. If both fields are restricted (ie, aren't *), the command will be run when either field matches the current time. For example,
''30 4 1,15 * 5''would cause a command to be run at 4:30 am on the 1st and 15th of each month, plus every Friday.