"Die 100 besten beim Qualifikationskampf zusammengelegter Server haben jeden Tag einmal die Möglichkeit, einen SS-Auftrag zu plündern. Bei jeder Plünderung eines SS-Auftrages danach werden 15 Goldbarren verbraucht"

Tranlates into "the top 100 of cross server Ranked Battle have the option to plunder a SS-Convoy. Each plunder afterwards costs 15 ingots."

Also Failing a "bought plunder" will result in an item which basically is a 100% refund of said 15 ingots used to plunder another time.

Nothing in the German Notes say anything about paying for plunder right from the beginning.

Each day you are able to accept 1 SS-Convoy and 1 plunder. SS-Convoys will grant you 30 coupons and if you get plundered you still get 25 coupons for completing it.