Why does my netgear WNDR 3700 not block iphones per schedule?

I've set my wndr 3700 router to block internet service during certain days and time table. It seems to be work in blocking connections from computers via ethernet and computers via wifi but fails to block internet service to iphones connected to the router via wifi. The router use to function properly, but this problem occurred within the last 2~3 months after I changed my cable modem box for one that I purchased myself (note that internet service is up and running properly),

Any ideas why this is happening and how I may fix this issue?

Check your router's date/time info