“追加备付款项”可以翻译为 "additional reserve payment" 或 "supplementary reserve fund payment"。
"additional reserve payment"：直接表达了“追加”和“备付款项”的含义，简洁明了。
"supplementary reserve fund payment"：其中“supplementary”意为“补充的”，“reserve fund”意为“储备金”，整体表达了“补充储备金的付款”，与“追加备付款项”意思相近。