On Wednesdays, the charge that applies is triple the regular swap. This is made in order to take the weekend into account.

The Swap charge occurs at 00:00 server time(there maybe a few minutes of delays), thus you can avoid to get charged higher by not holding a position at that time.

Please note that the swap points for both long and short positions, can change at anytime and they are not fixed. You may also monitor the swap points daily to know the exact costs/gains for holding positions overnight.