结算单位 meaning in Chinese

closing unit

All payments shall be settled in hong kong dollars
所有收费均以港币为结算单位。
The users are reminded to take note that the exchange rate of hong kong dollars against other currencies may fluctuate from time to time and if any user uses another currency as his base currency , the price of the good to him in such foreign currency may change from time to time
完成交易时亦将以港币为结算单位。用户须注意，港币与其他货币的兑换率会不时变动，如任何用户采用其他货币为基本货币，货品的价格以该种外币计算，可能会不时变动。