Castle Siege Event will start with 1 hour earlier for most countries which are not changing clocks including Philippines due Daylight Saving Time – DST – Summer Time. CS will start in 9 PM instead 10 PM (+8UTC/PH time) and for the players with the same timezone as the server (utc+3) the time will remain the same: 4PM-6PM (utc+3). Count down "time till the battle" on cs stats page will give you the best idea when CS starts in case any misunderstandings you might have. 
Siege Warfare Timeline
Guild Registration period : Sunday 00:00am ~ Monday 00:00am UTC+3;
Registration period for Sign of Lord : Tuesday 00:01am ~ Thursday 00:00am UTC+3;
Announcement : Friday 1:00pm UTC+3;
Castle Preparation : Friday 01:01pm ~ Saturday 08:00pm UTC+3;
Siege Warfare : Saturday 4:00pm - 6:00pm in UTC+3 -Server Time
Siege Warfare : Saturday 10:00am - 12:00pm (UTC-03:00) (Argentina)
Siege Warfare : Saturday 9:00am - 11:00am (UTC-04:00) (United States of America)
Siege Warfare : Saturday 9:00am - 11:00am (UTC-04:00) (Venezuela)
Siege Warfare : Saturday 8:00am - 10:00am (UTC-05:00) (Peru)
Siege Warfare : Saturday 3:00pm - 5:00pm (UTC+2:00) (Poland, Hungary & Serbia)
Siege Warfare : Saturday 4:00pm - 6:00pm (UTC+03:00) (Bulgaria, Greece, Romania & Turkey)
Siege Warfare : Saturday 5:00pm - 7:00pm (UTC+04:00) (Azerbaijan & Georgia)
Siege Warfare : Saturday 8:00pm - 10:00pm (UTC+07:00) (Vietnam)
Siege Warfare : Saturday 9:00pm - 11:00pm (UTC+08:00) (Philippines)
Siege Warfare Timeline
Guild Registration period : Sunday 00:00am ~ Monday 00:00am UTC+3;
Registration period for Sign of Lord : Tuesday 00:01am ~ Thursday 00:00am UTC+3;
Announcement : Friday 1:00pm UTC+3;
Castle Preparation : Friday 01:01pm ~ Saturday 08:00pm UTC+3;
Siege Warfare : Saturday 4:00pm - 6:00pm in UTC+3 -Server Time- Siege Warfare in other countries:
Siege Warfare : Saturday 10:00am - 12:00pm (UTC-03:00) (Argentina) Siege Warfare : Saturday 9:00am - 11:00am (UTC-04:00) (United States of America) Siege Warfare : Saturday 9:00am - 11:00am (UTC-04:00) (Venezuela) Siege Warfare : Saturday 8:00am - 10:00am (UTC-05:00) (Peru) Siege Warfare : Saturday 3:00pm - 5:00pm (UTC+2:00) (Poland, Hungary & Serbia) Siege Warfare : Saturday 4:00pm - 6:00pm (UTC+03:00) (Bulgaria, Greece, Romania & Turkey) Siege Warfare : Saturday 5:00pm - 7:00pm (UTC+04:00) (Azerbaijan & Georgia) Siege Warfare : Saturday 8:00pm - 10:00pm (UTC+07:00) (Vietnam) Siege Warfare : Saturday 9:00pm - 11:00pm (UTC+08:00) (Philippines)